331.

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

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

5 mL of 0.4 N NaOH is mixed with 20 mL of 0.1 N HCl.The pH of the resulting solution will be

• 7

• 8

• 5

• 6

The pH of the solution obtained by mixing 100 ml of a solution of pH = 3 with 400 mL of a solution of pH = 4 is

• 7 - log 2.8

• 4 - log 2.8

• 5 - log 2.8

• 3 - log 2.8

The equilibrium constant of the reaction

A (s) + 2B²⁺ (aq) $\rightleftharpoons$ A²⁺ (aq) + 2B (s);

E${}_{\mathrm{cell}}^{°} = 0.0295 \mathrm{V}\hspace{0.17em}\mathrm{is} \left[\frac{2.303 \mathrm{RT}}{\mathrm{F}} = 0.059\right]$

• 2 × 10²

• 3 × 10²

• 2 × 10⁵

• 10

An example for a neutral buffer is

• ammonium hydroxide and ammonium chloride

• acetic acid and sodium acetate

• acetic acid and ammonium hydroxide

• citric acid and sodium citrate

Conjugate base of H₂PO${}_4^{2-}$

• H₃PO${}_4^{-}$

• HPO${}_4^{2-}$

• H₃PO₄

• PO${}_4^{3-}$

For Cr₂O${}_7^{2-}$ + 14 H⁺ + 6e^- → 2Cr³⁺ + 7H₂O; E° = 1.33 V. At [Cr₂O${}_7^{2-}$] = 4.5 millimole, [Cr³⁺] = 15 millimole, E is 1.067 V. The pH of the solution is nearly equal to

• 2

• 3

• 5

• 4