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

If the density of some lake water is 1.25 g mL⁻¹ and contains 92 g of Na⁺ ions per kg of water, calculate the molality of Na⁺ ions in the lake.

If the solubility product of CuS is 6 × 10⁻¹⁶, calculate the maximum molarity of CuS in aqueous solution.

Calculate the mass percentage of aspirin (C₉H₈O₄) in acetonitrile (CH₃CN) when 6.5 g of C₉H₈O₄ is dissolved in 450 g of CH₃CN.

Nalorphene (C₁₉H₂₁NO₃), similar to morphine, is used to combat withdrawal symptoms in narcotic users. Dose of nalorphene generally given is 1.5 mg. Calculate the mass of 1.5 × 10⁻³ m aqueous solution required for the above dose.

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?

A reaction is first order in A and second order in B. How is the rate affected when the concentrations of both A and B are doubled?

In a reaction between A and B, the initial rate of reaction (r₀) was measured for different initial concentrations of A and B as given below:

What is the order of the reaction with respect to A and B?

Why is adsorption always exothermic?

Silver atom has completely filled d orbitals (4d¹⁰) in its ground state. How can you say that it is a transition element?

Explain giving reasons:

Transition metals and many of their compounds show paramagnetic behaviour.