21.

Arrange the following as per increasing, order of ionic size Mg²⁺, O^2-, Na⁺, F^-, N^3-

• N^3- < O^2- < F^-< Na⁺< Mg²⁺

• O^2- < F^-< N^3- < Mg²⁺ < Na⁺

• Na⁺< Mg²⁺ < O^2- < N^3- < F^-

• Mg²⁺ < Na⁺ < F^-< O^2-<N^3- 

How many crystal system are there when a≠b ≠c and a = b= c?

• 2,3

• 3,4

• 4,3

• 3,2

The cubic unit cell of a metal (molar mass = 63.55g mol^-1) has an edge length of 362 pm. Its density is 8.92 g cm^-3 . The type of unit cell is

• primitive

• face- centred

• body centred

• end centred

A radioactive sample is emitting 64 times radiations than non-hazardous limit. If its half life is 2h, after what time it become non-hazardous?

• 16h

• 12h

• 8h

• 4h

The decomposition of dinitrogen tetroxide at 300 K and 1.0 atm pressure is 20%, At equilibrium, the partial pressure (in atm) of nitrogen peroxide is

• 0.2

• 0.67

• 0.33

• 0.8

Of the following substances, the one which does not contain oxygen is

• bauxite

• dolomite

• cryolite

• epsomite

If E_a = 30 kcal mol^-1 ,what is the effect on rate constant of a reaction for 10°C rise in temperature? It will increase

• three-fold

• two-fold

• three and half-fold

• four-fold

For gaseous reaction, the following data is given

A → B, k₁ = 10¹⁵ e^-2000/T

C → D, k₂ = 10¹⁴ e^-1000/T

The temperature at which k₁ = k₂ is

• 2000 K

• 868.8 K

• 434.2 K

• 1000 K

What is the.standard potential of the Tl³⁺/ Tl electrode?

Tl³⁺ +2e^- → Tl⁺, E°= 1.26V

Tl⁺ +e^- → Tl, E°=-0.336V

• 0.924V

• -0.924 V

• 0.728 V

• -0.728V

One litre of 1 M CuSO₄ solution is electrolysed. After passing 2F charge, the molarity of CuSO₄ solution will be

• M/2

• Zero

• M/4

• M