21.

The hydrogen electrode is dipped in a solution of pH = 3 at 25°C .The potential of the cell would be ,

(the value of 2.303 RT/F is 0.059 V)

• 0.177 V

• 0.087 V

• -0.177 V

• 0.059 V

Which of the following solutions will have the highest boiling point ?

• 0.1 M FeCl₃

• 0.1 M BaCl₂

• 0.1 M NaCl

• 0.1 M urea

Azeotropic mixture of HCl and water has :

• 48% HCl

• 22.2% HCl

• 36% HCl

• 20.2% HCI

The activation energy for most of the reactions is approximately 50 kJ mol^-1 .The value of temperature coefficient for such reactions is :

• > 2

• > 3

• < 1

• > 4

Which of the following will form a colourless complex ?

• Ni²⁺

• Cu⁺

• Ti²⁺

• Fe³⁺

Phosgene is the common name of the following compound :

• Mixture of CO₂ and Cl₂

• POCl₃

• Carbonyl chloride

• Carbon tetrachloride

Which belongs to the actinide series ?

• Ce

• Cf

• Ca

• Cs

For a first order reaction at 27°C , the ratio of time required for 75% completion to 25% completion of reaction is :

• log $\frac{4}{3}$

• log $\frac{3}{4}$

• $\frac{\log 4}{\log 4/3}$

• $\frac{\log 4/3}{\log 4}$

If the rate of reaction , A $\to$ B doubles on increasing the concentration of A by 4 times , the order of the reaction is :

• 2

• 1

• 0.5

• 4

The group of elements in which the differentiating electrons enters in the antepenultimate shell of atoms are called :

• f - block elements

• p - block elements

• s - block elements

• d - block elements