Chemistry Test ...

The standard Gibb's free energy of the following reaction at 25^oC is 38484 J.

PCl₅ (g) PCl₃ (g) + Cl₂ (g)

The value of equilibrium constant is

If equivalent conductance of 1 M benzoic acid is 12.8 ohm^-1 cm², and the values of conductance of benzoate ion and H⁺ ion respectively are 42 and 288.42 ohm^-1 cm², then its degree of dissociation is:

The resistance of 0.01 N solution of an electrolyte was found to be 210 ohm at 298 K, using a conductivity cell of cell constant 0.66 cm⁻¹. The equivalent conductance of the solution is

Directions: The following question is based on the paragraph given below:

Chemical reactions involve interaction of atoms and molecules. A large number of atoms / molecules (approximately 6.023 ×10²³ ) are present in a few grams of any chemical compound varying with their atomic /molecular masses. To handle such large numbers conveniently, the mole concept was introduced.

This concept has implications in diverse areas such as analytical chemistry, biochemistry electrochemistry and radiochemistry. The following example illustrates a typical case, involving chemical/electrochemical reaction, which requires a clear understanding of the mole concept. A 4.0 molar aqueous solution NaCl is prepared and 500 mL of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrodes (Atomic mass : Na = 23, Hg = 200;1 Faraday = 96500 coulombs).

If the cathode is a Hg electrode, the maximum weight (g) of amalgam formed from this solution is

How many coulombs of electricity is required for the complete reduction of MnO₄^- in 500 ml of 0.5 M solution to Mn₂⁺ ions?

The energies of activation for forward and reverse reactions of A2 + B2 → 2AB are 180 kJ mol-1 and 200 kJ mol^-1 respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol^-1. The enthalpy change of the reaction (A2 + B2 → 2AB) in the presence of catalyst will be (in kJ mol^-1)

Hydrolysis of DDT is a first order reaction. Its half-life is 10 year. Time to hydrolyse 10 g DDT to half of its original amount is

The rate constant of a first order reaction is 3 * 10^-6 per second and initial concentration is 0.10 M. The initial rate of reaction is

For the reaction Cl₂ + 2I^- ⇒ I₂ + 2Cl^-, the initial concentration of I- was 0.20 mol L^-1 and the concentration after 20 min was 0.18 mol L^-1. The rate of formation of I2 in mol lit^-1 would be

Which of the following does not express the reaction rate for the above reaction?

Directions: The following question has four choices out of which ONLY ONE is correct.

The method usually employed for dispersion of a colloidal solution is

Coagulation of lyophobic colloids can be carried out by

Directions: The following question has four choices out of which ONLY ONE is correct.

Which of the following statements is not correct?

In adsorption, rate of physisorption increases when

A colloidal phase in which gas bubbles are dispersed in a liquid phase is known as