A buffer solution contains 0.1 mole of sodium acetate in 1000 cm³ of 0.1 M acetic acid. To the above buffer solution, 0.1 mole of sodium acetate is further added and dissolved. The pH of the resulting buffer is equal to

• pK_a - log2

• pK_a

• pK_a +2

• pK_a + log 2

The activation energy of  a reaction at a given temperature is found to be 2.303 RT J mol^-1. The ratio of rate constant to the Arrhenius factor is

• 0.01

• 0.1

• 0.02

• 0.001

pH value of which one of the following is not equal to one?

• 0.1 M CH₃COOH

• 0.1 M HNO₃

• 0.05 M H₂SO₄

• 50 cm³ 0.4 M HCl + 50 cm³ 0.2 M NaOH

A buffersolution contains 0.1 mole of sodium acetate dissolved in 1000 cm³ of 0.1 M acetic acid. To the above buffersolution, 0.1 mole of sodium acetate is further added and dissolved. The pH of the resulting buffer is 

• pK_a

• pK_a + 2

• pK_a - log 

• pK_a + log 2

H₂S is passed into one nm³ of a solution containing 0.1 mole of Zn²⁺ and 0.01 mole of Cu²⁺ till the sulphide ion concentration reaches to 8.1 × 10^-19 moles. Which one of the following statements is true?

[K_sp of ZnS and CuS are 3 × 10^-22 and 8 × 10^-36 respectively.]

• Only ZnS precipitates

• Both CuS and ZnS precipitate

• Only CuS precipitates

• No precipitation occurs

0.023 g of sodium metal is reacted with 100 cm³ of water. The pH of the resulting solution is

• 10

• 8

• 9

• 12

1 dm³ solution containing 10^-5 moles each of Cl^- ions and CrO${}_4^{2-}$ ions is treated with 10^-4 moles of silver nitrate. Which one of the following observations is made?

[K_spAg₂CrO₄ = 4 × 10^-12] and [K_spAgCl = 1 × 10^-10] 

• Precipitation does not occur

• Silver chromate gets precipitated first

• Silver chloride gets precipitated first

• Both silver chromate and silver chloride start precipitating simultaneously

pH value of which one of the following is not equal to one?

• 0.1 M HNO₃

• 0.05 M H₂SO₄

• 0.1 M CH₃COOH

• 50 cm³ of 0.4 M HCl + 50 cm³of 0.2 M NaOH

The yield of the products in the reaction A₂(g) + 2B(g) $\rightleftharpoons$C(g) + kJ would be higher at

• high temperature and high pressure

• high temperature and low pressure

• low temperature and high pressure

• low temperature and low pressure

670.

The equilibrium constant of a reaction is 0.008 at 298 K. The standard free energy change of the reaction at the same temperature is

• -11.96 kJ

• -5.43 kJ

• -8.46 kJ

• +11.96 kJ