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The redox reactions from the following are:

C(s)+O₂(g)→CO₂(g) as oxidation state of carbon is changing from 0 to +4 while for oxygen it is changing from 0 to -2 hence both oxidation and reduction are occurring respectively.

2Al(s)+3Sn²⁺(aq)→2Al³⁺(aq)+3Sn(s) here the oxidation state of aluminium is changing from 0 to +3 while for tin it is changing from +2 to 0 hence proving a redox reaction.

2Li(s)+I₂(g)→2LiI(s) in this oxidation state of lithium changes from 0 to +1 and that for iodine changes from 0 to -1 thus again a redox reaction.

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The activation energy of a chemical reaction can be increased or decreased by various factors. These factors can influence the rate of reaction and can result in a change in the potential energy barrier height. The height of the potential energy barrier in a chemical reaction is directly proportional to the energy of activation.

When the energy of activation of a system increases, the height of the potential energy barrier increases and the rate of reaction decreases.The height of the potential energy barrier corresponds to the amount of energy required to overcome the energy of activation. When the energy of activation is increased, the energy required to overcome the barrier also increases. This means that more energy is required to initiate the reaction and overcome the potential energy barrier. The rate of reaction decreases as a result of the increase in energy of activation. On the other hand, if the energy of activation decreases, the height of the potential energy barrier also decreases. This means that less energy is required to initiate the reaction and overcome the barrier. The rate of reaction increases as a result of the decrease in energy of activation.In summary, the height of the potential energy barrier increases when the energy of activation of a system increases. Conversely, the height of the potential energy barrier decreases when the energy of activation of a system decreases.

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The intermediate in the given reaction mechanism is O(g) (oxygen atom). Therefore, the correct answer is A) O(g).

In the reaction mechanism provided, O3(g) (ozone), O2(g) (oxygen molecule), and O(g) (oxygen atom) are the reactants. The reaction proceeds through a series of steps, and at some point, an intermediate is formed before the final products are obtained. In this case, the intermediate is O(g), which is an oxygen atom. This intermediate is then involved in further reactions to produce the final products. The other species mentioned in the options (O2(g) and O3(9)) are reactants or products and not the intermediates in this particular reaction mechanism.

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To identify the unknown metals X and Y, we need to compare their reduction potentials with the reduction potential of lead (Pb) given as E° = 0.3703 V. The reduction potential indicates the tendency of a species to gain electrons and undergo reduction.

If the measured cell potential for an unknown metal is greater than the reduction potential of Pb (0.3703 V), it means that the metal has a higher tendency to undergo reduction than Pb. On the other hand, if the measured cell potential is lower than the reduction potential of Pb, it means that the metal has a lower tendency to undergo reduction than Pb.

Let's consider the measured cell potentials for metals X and Y:

For metal X, if the measured cell potential is greater than 0.3703 V, it indicates that X has a higher tendency to undergo reduction than Pb.

For metal Y, if the measured cell potential is greater than 0.3703 V, it indicates that Y has a higher tendency to undergo reduction than Pb.

By comparing the measured cell potentials of X and Y with the reduction potential of Pb, we can identify which metal is X and which is Y based on their relative tendencies to undergo reduction compared to Pb.

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The volume of the sugar solution in the beaker is 0.5 liters.

The question at hand involves finding the volume of a sugar solution that has a concentration of 4 grams per liter when the total amount of sugar in the beaker is 2 grams.

Here is the solution:Let V be the volume of the sugar solution in the beaker. The concentration of sugar is 4 grams/liter. Thus, the total amount of sugar in V liters of the sugar solution is 4V grams of sugar. The problem states that the total amount of sugar in the beaker is 2 grams.

Therefore:4V = 2V = 2/4 = 0.5 liters. Therefore, the volume of the sugar solution in the beaker is 0.5 liters.

:The volume of the sugar solution in the beaker is 0.5 liters.

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Based on the groups in the periodic table, the atom that could represent "x" in the stable molecule LiX, where Li is lithium, would be any atom from Group 17, also known as the halogens.

The halogens include elements such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

Lithium, being in Group 1, has a single valence electron that it can donate to another atom to form a stable molecule. The halogens in Group 17 have a valence electron deficiency of one, making them suitable candidates to accept the electron from lithium and form a stable LiX molecule.

Therefore, elements like fluorine (F), chlorine (Cl), bromine (Br), iodine (I), or astatine (At) could represent the atom "x" in the LiX molecule.

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Several reagents can be used to effect addition to a double bond, including acid and water, hydroboration-oxidation reagents, and oxymercuration-demercuration reagents. The reasons why oxymercuration-demercuration was chosen to effect the following transformation instead of the other reagents are as follows:

1. Oxymercuration-demercuration reagents prevent sigmatropic rearrangements

2. Hydroboration-oxidation reagents yield the anti-Markovnikov product of addition.

3. The reaction requires the Markovnikov product without sigmatropic rearrangement.

The answer is option A, option D, and option F.

Oxymercuration-demercuration reagents are used to prevent sigmatropic rearrangements. The product produced by the hydroboration-oxidation of alkene is the anti-Markovnikov product of addition while oxymercuration-demercuration reagents give the Markovnikov product of addition. The reaction required the Markovnikov product without sigmatropic rearrangement.Therefore, the reasons why oxymercuration-demercuration was chosen to effect the following transformation instead of the other reagents are oxymercuration-demercuration reagents prevent sigmatropic rearrangements, hydroboration-oxidation reagents yield the anti-Markovnikov product of addition, and the reaction requires the Markovnikov product without sigmatropic rearrangement. The answer is option A, option D, and option F.

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If a saturated solution of a solute is made using 41.0 g of H2O at 20.0 °C, the amount of additional solute that can be added when the temperature is increased to 30.0 °C depends on the solubility of the solute. The solubility of most substances tends to increase with temperature, so more solute can be dissolved. The specific solubility data or a solubility curve is needed to determine the exact amount of additional solute that can be added.

When the temperature of a solvent increases, the solubility of many substances generally increases as well. This means that more solute can be dissolved in the solvent. However, the amount of additional solute that can be added when the temperature is increased from 20.0 °C to 30.0 °C depends on the solubility characteristics of the specific solute.

To determine the exact amount of additional solute that can be added, one would need to consult the solubility data or a solubility curve for the particular solute at different temperatures. These resources provide information on the maximum amount of solute that can be dissolved in a given amount of solvent at various temperatures. By referring to the solubility data, one can find the maximum solubility of the solute at 30.0 °C and calculate the difference between the currently saturated solution and the new solubility value to determine how much more solute can be added.

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The preferred chair to sit on a sunny day is the one made of aluminum. It offers a more comfortable seating experience compared to the iron chair. The aluminum chair's higher specific heat capacity helps it absorb less heat and stay cooler.

Aluminum is the preferred choice for sitting on a sunny day due to its higher specific heat capacity (c=0.89 J/g°C) compared to iron (c=0.45 J/g°C). Specific heat capacity refers to the amount of heat energy required to raise the temperature of a substance by one degree Celsius per gram.

When exposed to the sun, both chairs will absorb heat energy from the sunlight. However, aluminum has a higher specific heat capacity, meaning it can absorb more heat energy per gram compared to iron. This results in the aluminum chair heating up at a slower rate than the iron chair.

The slower rate of heat absorption by the aluminum chair makes it more comfortable to sit on during a sunny day. It will take longer for the aluminum chair to reach an uncomfortable temperature compared to the iron chair, providing a more pleasant seating experience.

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In the equation  [tex]2Mg + O_2 - > 2MgO[/tex], the coefficient of the oxygen molecule is 1.

In the given equation, the coefficients represent the number of moles or molecules of each substance involved in the reaction. The coefficient in front of a chemical formula indicates the ratio of moles or molecules of that substance compared to other substances in the reaction.

In this case, we have:

[tex]2Mg + O_2 - > 2MgO[/tex]

The coefficient of O2 is 1. This means that for every 1 molecule or mole of O2, there are 2 moles or molecules of Mg involved in the reaction. The coefficient "1" indicates that only one molecule or mole of O2 is required for the reaction to take place.

It's important to note that coefficients can be used to balance chemical equations by ensuring that the number of atoms on each side of the equation is equal. In this equation, the coefficient "1" in front of O2 indicates that there is one molecule or mole of O2 on both sides of the equation, making it balanced.

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The correct answer among the following is option C which is Tempera paint.

Explanation: A colloid is a heterogeneous mixture in which one substance is dispersed throughout another substance. The dispersed substance can either be a solid, liquid or gas and is referred to as the dispersed phase or internal phase and the substance in which it is dispersed is called the continuous phase or external phase. In tempera paint, pigment is dispersed throughout an emulsion of water and egg yolk, making it a colloid.

Brass is an alloy of copper and zinc, and is therefore a homogeneous mixture. Air is a mixture of gases, and is not a colloid. An opal is a mineral and not a mixture. Therefore, the correct answer is option C which is Tempera paint.

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The length of time it takes for an object to complete one full orbit around another object is known as the orbital period. The amount of time it takes for an item to return to the same place in its orbit is another way to put this. The orbital period is 1.79 × 10³⁷ s.

The smallest velocity that a body must sustain to remain in orbit is called orbital velocity. The tendency of the moving body to move forward in a straight line is caused by its inertia.

The expression used to calculate orbital velocity is:

v₀ = √GM/R

Where 'G' is the gravitational constant, 'M' is the mass of the earth, and 'R' is the radius of the earth.

The orbital period is:

T = 2πR / v₀

T² = 4π²R³ / GM

M =  6 × 10²⁴ Kg

G = 6.67 × 10⁻¹¹

T² = 4 × 3.14²×  (3.20 × 10⁷)³ /  6.67 × 10⁻¹¹ × 6 × 10²⁴

T = 1.79 × 10³⁷ s

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The correct answer is 2L.

The volume of the gas when the pressure increases to 9 am at the same constant temperature.According to Boyle’s law: V1P1 = V2P2 where:V1 = initial volume = 6LP1 = initial pressure = 3 atmV2 = final volume, unknownP2 = final pressure = 9 atmSubstitute the known values into the equation:V1P1 = V2P26L(3 atm) = V2(9 atm)18 atm L = 9 atm V218 atm L/9 atm = V2V2 = 2 LTherefore, the volume of the gas when the pressure increases to 9 atm at the same constant temperature is 2 L. Hence, the answer is A. 2L.

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The ending generally associated with a monatomic anion is option D, "...ide."

Monatomic anions are formed when an atom gains one or more electrons, resulting in a negatively charged ion.

The names of monatomic anions typically end in "...ide."

To illustrate this, let's consider a few examples:

- Chlorine, an element in Group 17 of the periodic table, forms a monatomic anion by gaining one electron. The resulting ion is called chloride (Cl^-).

- Oxygen, an element in Group 16 of the periodic table, forms a monatomic anion by gaining two electrons. The resulting ion is called oxide (O^2-).

- Nitrogen, an element in Group 15 of the periodic table, forms a monatomic anion by gaining three electrons. The resulting ion is called nitride (N^3-).

From these examples, we can observe that the names of monatomic anions end in "...ide."

In conclusion, the ending generally associated with a monatomic anion is option D, "...ide."

This ending is characteristic of anions formed when atoms gain electrons to achieve a stable electron configuration.

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Given the equation:2A(g) ⇌ B(g) + C(g)AH' = +27 kJK = 3.2 x 10⁻⁴Which of the following would be true if the temperature were increased from 25°C to 100°C?1. The value of K would be smaller2. The concentration of A(g) would be increased3.

The concentration of B(g) would increaseNow let's consider the effect of increasing the temperature from 25°C to 100°C on the given reaction. The endothermic reaction absorbs heat, so it can be written as:2A(g) ⇌ B(g) + C(g) + heatThe increase in temperature causes an increase in the heat term. This, in turn, shifts the equilibrium to the right, leading to an increase in the concentration of the products (B and C) and a decrease in the concentration of the reactant (A). Therefore, the correct options are:b. 3 only (The concentration of B(g) would increase) and d. 2 only (The concentration of A(g) would be increased) when the temperature is increased from 25°C to 100°C.Option 1 is false. If the temperature is increased, the value of K would be higher.Option 2 is true. If the temperature is increased, the concentration of A(g) would decrease. Option 3 is true. If the temperature is increased, the concentration of B(g) and C(g) would increase.

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The first indirect effect of aerosols is the increase in cloud albedo. The sign of its radiative forcing is negative.

Aerosols play a major role in the earth's climate by scattering and absorbing solar radiation and modifying the microphysical and radiative properties of clouds. The first indirect effect of aerosols is the increase in cloud albedo.The albedo effect happens when radiation from the sun reflects off the planet and back into space. Clouds act as mirrors and reflect much of the sun's radiation back into space, making the Earth cooler. Aerosols increase cloud albedo, reflecting more radiation back into space, and causing the Earth's temperature to decrease. The sign of the radiative forcing of the first indirect effect of aerosols is negative.

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The correct option among the given options in the question is false statement about isotopes is Isotopes are atoms with the same atomic number but different mass numbers.

The definition of isotopes states that isotopes are atoms of the same element that have different numbers of neutrons. For instance, carbon has three isotopes: carbon-12, carbon-13, and carbon-14.Isotopes are atoms with the same atomic number but different mass numbers because they have the same number of protons and electrons as the element, but a different number of neutrons. The number of neutrons determines the isotope.

Option C is the correct answer of this question.

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The heat transferred when 4.5 grams of Carbon reacts with H2O is approximately 42.38 kJ. Therefore, the correct option is 42 kJ absorbed.

Option B.

Given reaction is as follows: C(s) + H2O(g) + 113 kJ → CO(g) + H2(g)To find the amount of heat transferred when 4.5 grams of Carbon reacts with H2O, we have to first find the amount of moles of Carbon present. The molar mass of Carbon is 12 g/mol. Therefore, the amount of moles of Carbon can be calculated as follows:mass of carbon/molar mass of carbon=4.5 g/12 g/mol=0.375 molNow, to find the amount of heat transferred, we use the equation, q = n∆Hwhere q is the heat transferred, n is the amount of moles of Carbon present, and ∆H is the enthalpy change for the given reaction. ∆H is given in the equation as 113 kJ.To find the sign of ∆H, we look at the reactants and products. In the given reaction, Carbon reacts with H2O to form CO and H2. Since Carbon and H2O are reactants and CO and H2 are products, this reaction is an endothermic reaction. Hence, the value of ∆H is positive.∆H = 113 kJ/molNow, substituting the values in the equation, q = n∆Hq = 0.375 mol × 113 kJ/molq = 42.38 kJ (approx)

Option B.

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The emission spectrum of hydrogen was used to calibrate the spectroscope because hydrogen has a relatively simple and well-understood atomic structure.

The simplest and most prevalent element in the universe is hydrogen. Its atomic structure is made up of one electron orbiting the nucleus in various energy levels or orbitals and a single proton in the nucleus.

An electron emits energy in the form of light at particular wavelengths or frequencies when it moves from a higher energy level to a lower energy level. The hydrogen spectral lines, which are a distinctive pattern of lines in the emission spectrum, are produced by these wavelengths.

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An increase in temperature of ten degrees Celsius will typically have a significant effect on the rate of a reaction. The specific outcome, whether the rate doubles, quadruples, is halved, or depends on the reaction, depends on the nature of the reaction and the associated rate equation.

The effect of temperature on the rate of a reaction can be determined by the Arrhenius equation and the concept of reaction rate constant (k). In general, an increase in temperature leads to an increase in the rate of a reaction. The Arrhenius equation states that the rate constant (k) is exponentially dependent on temperature (T) through the term exp(-Ea/RT), where Ea is the activation energy, R is the gas constant, and T is the absolute temperature.

When the temperature increases, the exponential term in the Arrhenius equation becomes larger, resulting in a higher rate constant. As a consequence, the rate of the reaction tends to increase. However, the exact relationship between temperature and rate depends on the specific rate equation for the reaction. Therefore, without knowledge of the specific reaction and its rate equation, it is not possible to determine the exact outcome of increasing the temperature by ten degrees Celsius. It could lead to the rate doubling, quadrupling, being halved, or having a different effect altogether, depending on the particular reaction and its associated rate equation.

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The change in enthalpy (ΔH) for the reaction 2NaHSO4(s) ⟶ Na2SO4(s) + H2O(g) + SO3(g) is given as -231.3 kJ. To determine the change in enthalpy when 3.60 g of NaHSO4 reacts, we need to calculate the moles of NaHSO4 and then use the stoichiometry of the reaction to find the corresponding change in enthalpy.

To calculate the moles of NaHSO4, we divide the given mass (3.60 g) by its molar mass. The molar mass of NaHSO4 is the sum of the atomic masses of sodium (Na), hydrogen (H), sulfur (S), and four oxygen (O) atoms:

Molar mass of NaHSO4 = 22.99 g/mol + 1.01 g/mol + 32.07 g/mol + (4 × 16.00 g/mol) = 120.05 g/mol

Moles of NaHSO4 = mass / molar mass = 3.60 g / 120.05 g/mol ≈ 0.03 mol

The change in enthalpy is given per mole of NaHSO4, so to find the change in enthalpy for 0.03 mol, we multiply the given value of ΔH (-231.3 kJ/mol) by the number of moles:

Change in enthalpy = ΔH × moles = -231.3 kJ/mol × 0.03 mol ≈ -6.939 kJ

Therefore, the change in enthalpy for the reaction, when 3.60 g of NaHSO4 reacts, is approximately -6.939 kJ (rounded to three decimal places).

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When the weak acid HCN (hydrocyanic acid) dissolves in water, it forms the hydronium ion (H3O+) and the cyanide ion (CN-).

The balanced chemical equation for the reaction of HCN with water is: HCN (aq) + H2O (l) ⇌ H3O+ (aq) + CN- (aq)The Ka expression for this reaction is as follows:Ka = [H3O+][CN-] / [HCN]Where [H3O+] represents the concentration of the hydronium ion, [CN-] represents the concentration of the cyanide ion, and [HCN] represents the concentration of HCN.The Ka expression can be used to calculate the acid dissociation constant, which is a measure of the strength of the acid. The larger the Ka value, the stronger the acid. The Ka expression can also be used to calculate the pH of the solution.

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Calcium has a larger atomic radius than magnesium because of the additional electron shell.

The atomic radius is the measure of the size of an atom, typically defined as the distance from the nucleus to the outermost electron shell. In the case of calcium and magnesium, both elements are in the same period (row) of the periodic table, so they have the same number of electron shells.

However, calcium has a larger atomic radius than magnesium because calcium has more protons in its nucleus, which leads to a stronger attraction on the electrons and causes the electron cloud to expand further. Therefore, the additional electron shell in calcium compared to magnesium is responsible for its larger atomic radius.

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HIO₃ is a strong acid, it will release a higher concentration of H⁺ ions, leading to a greater concentration of hydroxide ions compared to the other species listed. Hence, option C is correct.

The species that will produce the greatest concentration of hydroxide ions in solution is option C: HIO₃.

HIO₃ is an acid called iodic acid. When it dissolves in water, it will dissociate to release H⁺ ions and IO₃⁻ ions. The H⁺ ions can react with water molecules to form hydronium ions (H₃O⁺), while the IO₃⁻ ions do not directly produce hydroxide ions.

However, in the presence of excess water, the hydronium ions can react with water in a reversible reaction to generate hydroxide ions (OH⁻). This reaction is known as the autoionization of water:

2H₃O⁺ (hydronium ions) ⇌ H₂O + H₃O⁺ + OH⁻

As a result, the concentration of hydroxide ions (OH⁻) increases in the solution. Since HIO₃ is a strong acid, it will release a higher concentration of H⁺ ions, leading to a greater concentration of hydroxide ions compared to the other species listed.

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The compound that will not be soluble in water is BaSO₄ (barium sulfate). Option B is correct.

BaSO₄ (barium sulfate) is the compound that is not soluble in water. Solubility in water depends on the nature of the compound and the interactions between its constituent ions and water molecules. In the case of BaSO₄, the strong electrostatic forces of attraction between the barium (Ba²⁺) and sulfate (SO₄²⁻) ions result in a very low solubility in water. The solubility rules dictate that most sulfates are soluble in water, but barium sulfate is an exception.

It forms a solid precipitate when barium ions and sulfate ions come into contact in an aqueous solution. On the other hand, K₂S (potassium sulfide), NaNO₃ (sodium nitrate), and LiOH (lithium hydroxide) are all soluble in water and will dissociate into their constituent ions when dissolved, resulting in a homogeneous solution. Option B is correct.

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A "percolating stream" is a stream from which water is moving downward to the water table.

A percolating stream generally refers to a type of stream or water flow that occurs when water moves downward through permeable materials such as soil, sand, or rock, gradually infiltrating into the ground. The water follows a vertical or nearly vertical path, seeping through the interconnected spaces and pores within the subsurface layers.

This movement is often driven by gravity, as water percolates or filters through the porous medium. Percolating streams contribute to groundwater recharge, replenishing underground water reservoirs and influencing the overall hydrological cycle.

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Hydrazine, N2H4 is a weak base. Its dissociation process in water is: N2H4 + H2O ↔ N2H5+ + OH¯Given the base dissociation constant, Kb = 1.3 × 10⁻⁶ M.Hydrazine (N2H4) is a weak base that undergoes hydrolysis when dissolved in water.

A hydrolysis reaction occurs when a molecule reacts with water to create an acidic or basic solution. The pH of a 0.10 mm solution of hydrazine, N2H4, with Kb of 1.3×10−6 can be calculated as follows:Step 1: Calculate the concentration of OH- ions produced when N2H4 undergoes hydrolysis.N2H4 + H2O → N2H5+ + OH-Initial concentration = 0.10 mol/L0.10 ----- 0 ----- 0After hydrolysis, the amount of OH- produced is x, so the concentration of OH- is x mol/L.Using the Kb value and the equation:Kb = [N2H5+][OH-] / [N2H4][OH-] = Kb * [N2H4] / [N2H5+]x^2 / (0.10 - x) = 1.3 × 10⁻⁶x^2 = (1.3 × 10⁻⁶)(0.10 - x)x = [OH⁻] = 1.13 × 10⁻⁵ MStep 2: Calculate the pOHpOH = -log [OH⁻] = -log (1.13 × 10⁻⁵)= 4.95Step 3: Calculate the pHpH = 14 - pOH = 14 - 4.95 = 9.05Therefore, the pH of a 0.10 mm solution of hydrazine, N2H4, with Kb of 1.3×10−6 is 9.05.

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a) Calculation of pH of the given buffer:Given, Mass of (CH3)2NH2I = 49.9 gVolume of (CH3)2NH2I solution = 250.0 mLConcentration of (CH3)2NH = 1.42M= 1.42 moles/L

Let's first calculate the moles of (CH3)2NH and (CH3)2NH2+CH3NH2+(aq) ⇌ CH3NH3+(aq) + OH-(aq)Kb = 5.4 × 10^-4Kw = 1.0 × 10^-14Kb = [CH3NH3+][OH-]/[CH3NH2+][OH-]= [CH3NH3+]/[CH3NH2+][OH-]Initial concentration of CH3NH2+ = 1.42MInitial concentration of CH3NH3+ = 0pH of the buffer is calculated using the following formula:pH = pKa + log [A-]/[HA]The pKa of (CH3)2NH is 10.73, and at pH 10.73, the ratio [A-]/[HA] is 1, so the pH of the buffer can be calculated from the following equation:pH = pKa + log [A-]/[HA]pH = 10.73 + log (0.0045/0.0045)pH = 10.73b) Calculation of pH of buffer after addition of 0.300 mol of H+:The balanced chemical equation for the addition of H+ is:CH3NH2(aq) + H+(aq) ⇌ CH3NH3+(aq)Initial concentration of CH3NH2+ = 1.42 MInitial concentration of CH3NH3+ = 0 molesLet x be the concentration of H+ after it is added.CH3NH2+(aq) + H+(aq) ⇌ CH3NH3+(aq)H+ is consumed by CH3NH2 and added to CH3NH3+.[H+] = [CH3NH3+] - [CH3NH2+]Let [CH3NH2+] = y[H+] = 0.3 mol/L – y[CH3NH3+] = yKb = [CH3NH3+][OH-]/[CH3NH2+][OH-]5.4 × 10^-4 = y(0.3-y)/ yMoles of CH3NH3+ = yMoles of CH3NH2+ = 0.42 - y1.42 = (y/0.3-y)y = 0.042 mol/L[OH-] = Kb * [CH3NH3+]/[CH3NH2+]5.4 × 10^-4 = 0.042(0.042)/0.258pOH = 3.298pH = 14 – 3.298 = 10.702c) Calculation of pH of buffer after the addition of 0.120 mol of OH-:The balanced chemical equation for the addition of OH- is:CH3NH2(aq) + OH-(aq) ⇌ CH3NH3+(aq) + H2O(l)Initial concentration of CH3NH2+ = 1.42 MInitial concentration of CH3NH3+ = 0 molesLet x be the concentration of OH- after it is added.CH3NH2+(aq) + OH-(aq) ⇌ CH3NH3+(aq) + H2O(l)OH- is consumed by CH3NH3+ and added to CH3NH2+.[OH-] = [CH3NH2+] - [CH3NH3+]Let [CH3NH2+] = y[OH-] = 0.120 mol/L – y[CH3NH3+] = yKb = [CH3NH3+][OH-]/[CH3NH2+][OH-]5.4 × 10^-4 = y(y)/ (1.42 – y)Moles of CH3NH3+ = yMoles of CH3NH2+ = 1.42 – y(5.4 × 10^-4 = y^2 / (1.42 – y)0 = y^2 – 5.4 × 10^-4 y – 7.668 × 10^-4y = (0.00054 ± sqrt((5.4 × 10^-4)^2 + 4(7.668 × 10^-4)) / 2 = 0.00729 mol/LCH3NH2+ = 1.42 – y = 1.41 M[OH-] = Kb * [CH3NH3+]/[CH3NH2+]5.4 × 10^-4 = y(0.00729)/1.41[OH-] = 2.786 × 10^-6pOH = 5.56pH = 8.44 (as pOH + pH = 14)

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