HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

Write the chemical equation involved in the following reaction:

Hoffmann-bromamide degradation reaction

Gas (A) is more soluble in water than Gas (B) at the same temperature. Which one of the two gases will have the higher value of KH (Henry’s constant) and why

The conductivity of 0.001 mol L-1 solution of CH₃COOH is 3.905× 10-5 S cm-1. Calculate its molar conductivity and degree of dissociation (α) Given λ°(H⁺)= 349.6 S cm² mol-1 and λ°(CH₃COO)= 40.9S cm²mol^-1.

Why do gases always tend to be less soluble in liquids as the temperature is raised?

A first order reaction takes 23.1 minutes for 50% completion. Calculate the time required for 75% completion of this reaction.

(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)

Define limiting molar conductivity.

Why conductivity of an electrolyte solution decreases with the decrease in concentration ?

A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.

(log 2 = 0.3010)

The conductivity of 0.20 mol L⁻¹ solution of KCl is 2.48 × 10⁻² S cm⁻¹. Calculate its molar conductivity and degree of dissociation (α). Given λ⁰ (K⁺) = 73.5 S cm² mol⁻¹ and λ⁰ (C1⁻) = 76.5 S cm² mol⁻¹.

Why does the conductivity of a solution decrease with dilution?

Explain the principle of the method of electrolytic refining of metals. Give one example.

Define the following terms: Molar conductivity (⋀_m)

Explain ionic solids are hard and brittle.

Copper crystallises into a fcc lattice with edge length 3.61 × 10⁻⁸ cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm⁻³.

An ionic compound crystallises in FCC type structure with ‘A’ ions at the centre of each face and ‘B’ ions occupying corners of the cube. The formula of compound is _______.

0.05 M NaOH solution offered a resistance of 31.6 Ω in a conductivity cell at 298 K. If the cell constant of the cell is 0.367 cm^-1, calculate the molar conductivity of NaOH solution.

Which of the following vitamins is the vitamin of alicyclic series?

(A) Vitamin C

(B) Vitamin K

(C) Vitamin B

(D) Vitamin A

The unit of rate constant for zero order reaction is _______.

(A) t^–1

(B) mol dm^–3 t^–1

(C) mol^–1 dm³ t^–1

(D) mol^–2 dm⁶ t^–1

10.0 grams of caustic soda when dissolved in 250 cm³ of water, the resultant gram molarity of solution is _______.

(A) 0.25 M

(B) 0.5 M

(C) 1.0 M

(D) 0.1 M

Classify the following solids into different types:

a. Ammonium phosphate

b. Brass

c. S₈ molecule

d. Diamond