251.

The chemical decomposition of XY₂ occurs as ${\mathrm{XY}}_2\left(\mathrm{g}\right) \rightleftharpoons \mathrm{XY} \left(\mathrm{g}\right) + \mathrm{Y}\left(\mathrm{g}\right)$. The initial vapour pressure of XY₂ is 600 mm of mercury and at equilibrium it is 800 mm of mercury. Find out the value of K for this reaction when the volume of the system remains constant.

• 50

• 100

• 166.6

• 150

The degree of ionisation of decinormal solution of CH₃COOH is 1.3%. If the log of 1.3 is 0.11, the pH of this solution is

• 2.89

• 3.89

• 4.89

• 0.89

A buffer solution is obtained by mixing 10 mL of 1.0M CH₃COOH and 20mL of 0.5M CH₃COONa and it is diluted to 100mL using distilled water. pK_a of CH₃COOH is 4.76. The pH of this buffer solution is 

• 2.76

• 3.76

• 4.76

• 0.76

1.0 L of 1.0 M solution of sodium hydroxide is neutralised by 1.0 L of 1.0 M of methanoic acid. If the heat of formation of water is X, the neutralisation energy of above reaction is

• less than X

• more than X

• equal to X

• None of the above

The standard emf of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 25°C. The equilibrium constant of the reaction would be

• 2.0 × 10¹¹

• 4.0 × 10¹²

• 1.0 × 10²

• 1.0 × 10¹⁰

Which is the weakest acid out out of HF, HCl, HBr and HI?

• HF

• HCl

• HBr

• HI

Which of the following is a wrong statement about equilibrium state?

• Rate of forward reaction=Rate of backward reaction

• Equilibrium is dynamic

• Catalysts increase value of equilibrium constant

• Free energy change is zero

A + B $\rightleftharpoons$C + D. Initially moles of A and B are equal. At equilibrium, moles of C are three times that of A. The equilibrium constant of the reaction will be

• 1

• 3

• 4

• 9

$\mathrm{If} \mathrm{for} {\mathrm{N}}_2 + 3{\mathrm{H}}_2 \rightleftharpoons 2{\mathrm{NH}}_3, {\mathrm{K}}_{\mathrm{eq}} = 1.6 \times {10}^{-5},$ then the value of K_eq for the reaction ${\mathrm{NH}}_3 \rightleftharpoons \frac{1}{2}{\mathrm{N}}_2+ \frac{3}{2}{\mathrm{H}}_2 \mathrm{will} \mathrm{be}$

• 6.25

• 25

• 250

• 500

A weak acid HX has dissociation constant 10^-5. The pH of 0.1 M solution of this acid will be

• 2

• 3

• 4

• 5