31.

The standard emf of a cell , involving one electron change is found to be 0.591 V at 25^o C . The equilibrium constant of the reaction is :

(F = 96500 C mol^-1 , R = 8.314 JK^-1mol^-1)

• 1.0 x 10¹

• 1.0 x 10⁵

• 1.0 x 10¹⁰

• 1.0 x 10³⁰

The properties of Zr and Hf are same because :

• they have similar radii

• they belong to d-block

• they have same valence electrons

• None of the above

Which is not a colligative property ?

• Refractive index

• Lowering of vapour pressure

• Depression in freezing point

• Elevation in boiling point

If 8. 0 g of a radioactive isotope has a half-life of 10 yr .The half-life of 2.0 g of the same substance is :

• 2.5 yr

• 5 yr

• 20 yr

• lO yr

Formic acid can be distinguished from acetic acid by its reaction with :

• NaHCO₃

• Tollen's reagent

• NaOH

• None of these

Aspirin is prepared by the acetylation of salicylic acid with :

• phenol

• acetic anhydride

• methyl acetate

• chlorine

Among the following, the correct order of basicity is :

• NH₂^- > OH^- > RO^- > RCOO^-

• NH₂^- > RO^- > OH^- > RCOO^-

• RCOO^- > NH₂^- > RO^- > OH^-

• RCOO^- > RO^- > NH₂^- > OH^-

Cannizaro reaction is not given by :

• acetaldehyde

• formaldehyde

• benzaldehyde

• triethyl acetaldehyde

Which enzyme converts glucose to ethanol ?

• Diastase

• Invertase

• Zymase

• Both (b) and (c)

Which of the following reaction follows S_N1 mechanism ?

• (CH₃)₂C-CH₂Cl + CH₂OK

• (CH₃)₂C-CH₂Cl + HCl

• (CH₃)₃C-Cl + NaOH

• (CH₃)₂CHI + H₂O