The molecular formula of a commercial resin used for exchanging ions in water softening is C₈H₇SO₃Na ( mol. wt = 206). What would be the maximum uptake of Ca²⁺ ions by the resin when expressed in mole per gram resin?

• 1/103

• 1/206

• 2/309

• 2/309

Which of the following is the energy of a possible excited state of hydrogen?

• +13.6 eV

• -6.8 eV

• -3.4 eV

• -3.4 eV

The intermolecular interaction that is dependent on the inverse cube of the distance between the molecule is:

• ion-ion interaction

• ion-dipole interaction

• London force

• London force

The following reaction is performed at 298 K
2NO(g) + O₂ (g) ⇌ 2NO₂ (g)
The standard free energy of formation of NO (g) is 86.6 kJ/mol at 298 K. What is the standard free energy of formation of NO₂ (g) at 298 K? (K_P = 1.6 x 10¹²)

• R (298) In (1.6 x 10¹²)-86600

• 86600 + R (298) In (1.6 x 10¹²)

• 86600 - In(1.6 x 10¹²)/R(298)

• 86600 - In(1.6 x 10¹²)/R(298)

The standard Gibbs energy change at 300 K for the reaction, 2A  ⇌ B +C is 2494.2J at a given time, the composition of the reaction mixture is and , The reaction proceeds in the [R= 8.314 JK/mol, e = 2.718]

• forward direction because Q>Kc

• reverse direction because Q>K_c

• forward direction because Q < Kc

• forward direction because Q < Kc

6.

The ionic radii (in Å) of N^3–, O^2– and F^– are respectively:

• 1.36, 1.40 and 1.71

• 1.36, 1.71 and 1.40

• 1.71, 1.40 and 1.36

• 1.71, 1.40 and 1.36

In Carius method of estimation of halogens, 250 mg of an organic compound gave 141 mg of AgBr. The percentage of bromine in the compound is: (at. Mass Ag = 108; Br = 80)

• 24

• 36

• 48

• 48

From the following statements regarding H₂O₂, choose the incorrect statement:

• It can act only as an oxidising agent

• It decomposed on exposure to light

• It has to be stored in plastic or wax lined glass bottles in dark

• It has to be stored in plastic or wax lined glass bottles in dark

Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?

• CaSO₄

• BeSO₄

• BaSO₄

• BaSO₄

Sodium metal crystallises in a body centred cubic lattice with a unit cell edge of 4.29 Å The radius of sodium atom is approximate:

• 1.86 Å

• 3.22Å

• 5.72 Å

• 5.72 Å