A buffer solution is obtained by mixing 10 mL of 1.0M CH3COOH and

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251.

The chemical decomposition of XY2 occurs as XY2(g)  XY (g) + Y(g). 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


252.

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


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253.

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. pKa of CH3COOH is 4.76. The pH of this buffer solution is 

  • 2.76

  • 3.76

  • 4.76

  • 0.76


C.

4.76

10 mL. 1.0M CH3COOH = 10N CH3COOH20mL 0.5 MCH3COONa = 10N CH3COONapH= pKa + log saltacid     = 4.76 + log1010= 4.76


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254.

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


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255.

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


256.

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

  • HF

  • HCl

  • HBr

  • HI


257.

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


258.

A + B 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


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259.

If for N2 + 3H2  2NH3, Keq = 1.6 × 10-5, then the value of Keq for the reaction  NH3 12N2+ 32H2 will be

  • 6.25

  • 25

  • 250

  • 500


260.

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


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