Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions

For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :

(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.

(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.

(Given log 2 = 0.3010, log 4 = 0.6021)

For a chemical reaction R → P, the variation in the concentration (R) vs. time (t) plot is given as:

(i) Predict the order of the reaction.

(ii) What is the slope of the curve?

(iii) Write the unit of rate constant for this reaction.

The following data were obtained during the first order thermal decomposition of SO₂Cl₂ at a constant volume :

SO₂Cl₂ (g) → SO₂ (g) + Cl₂ (g)

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

Give reasons for the following : (CH₃)₃ P = O exists but (CH₃)₃ N = O does not.

Describe the roles of the following: SiO₂ in the extraction of copper from copper matte

Name the method used for refining of copper metal.

Classify the following solids in different categories based on the nature of intermolecular forces operating in them:

Potassium sulphate, tin, benzene, urea, ammonia, water, zinc sulphide, graphite, rubidium, argon, silicon carbide.

Classify each of the following solids as ionic, metallic, molecular, network (covalent) or amorphous.

1. Tetra phosphorus decoxide (P₄O₁₀)
2. Ammonium phosphate (NH₄)₃PO₄
3. SiC
4. I₂
5. P₄
6. Plastic
7. Graphite
8. Brass
9. Rb
10. LiBr
11. Si

Define the term solution.

For a reaction, \[\ce{A + B -> Product}\]; the rate law is given by, `r = k[A]^(1/2)[B]^2`. What is the order of the reaction?

The conversion of molecules X to Y follows second order kinetics. If concentration of X is increased to three times how will it affect the rate of formation of Y?

From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.

\[\ce{3NO_{(g)} -> N2O_{(g)}}\] Rate = k[NO]²

From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.

\[\ce{H2O2_{( aq)} + 3I^-_{( aq)} + 2H^+ -> 2H2O_{(l)} + I^-_3}\] Rate = k[H₂O₂][I⁻]

From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.

\[\ce{CH3CHO_{(g)} -> CH4_{(g)} + CO_{(g)}}\] Rate = k [CH₃CHO]^3/2

From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.

\[\ce{C2H5Cl_{(g)} -> C2H4_{(g)} + HCl_{(g)}}\] Rate = k [C₂H₅Cl]

For the reaction:

\[\ce{2A + B → A2B}\] 

the rate = k[A][B]² with k = 2.0 × 10⁻⁶ mol⁻² L² s⁻¹. Calculate the initial rate of the reaction when [A] = 0.1 mol L⁻¹, [B] = 0.2 mol L⁻¹. Calculate the rate of reaction after [A] is reduced to 0.06 mol L⁻¹.

Mention the factors that affect the rate of a chemical reaction.

A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is doubled?

A reaction is first order in A and second order in B. Write the differential rate equation.

A reaction is first order in A and second order in B. How is the rate affected on increasing the concentration of B three times?