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

Observe the graph shown in figure and answer the following questions:

Write the relationship between k and t_1/2 (half-life period)

Account for the following:

Arrange the following compounds in the increasing order of their basic strength in aqueous solution: CH₃NH₂,(CH₃)₃N,(CH₃)₂NH

Explain the following reactions:

Clemmensen reaction

Write the main product in the following reaction:

\[\ce{CH3CH2CHO ->[Zn(Hg)/Conc. HCl]}\]

Arrange the following compounds in increasing order of their boiling points:

CH₃CH₂OH, CH₃−CHO, CH₃−COOH

Which isomer of C₅H₁₀ gives a single monochloro compound C₅H₉Cl in bright sunlight?

A first-order reaction is 50% complete in 30 minutes at 300 K and in 10 minutes at 320 K. Calculate activation energy (E_a) for the reaction. [R = 8.314 J K⁻¹ mol⁻¹]

[Given: log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021]

Calculate the Δ_rG⁰ and log K_c, for the given reaction at 298 K:

\[\ce{Ni_{(s)} + 2Ag^+_{( aq)} <=> Ni^{2+}_{( aq)} + 2Ag_{(s)}}\]

Given: `"E"_("Ni"^(2+)//"Ni")^0` = −0.25 V, `"E"_("Ag"^+//"Ag")^0` = +0.80 V, 1F = 96500 C mol⁻¹.

Among the following, which has the highest value of pK_b?

What happens to the rate constant k and activation energy E_a as the temperature of a chemical reaction is increased? Justify.

The complex [Co(NH₃)₅(NO₂)]Cl₂ is red in colour. Give IUPAC the name of its linkage isomer.

Why is the boiling point of o-dichlorobenzene higher than p-dichlorobenzene, but the melting point of para-isomer is higher than ortho-isomer?

Assertion (A): The half-life of a reaction is the time in which the concentration of the reactant is reduced to one-half of its initial concentration.

Reason (R): In first-order kinetics, when the concentration of reactant is doubled, its half-life is doubled.

Arrange the isomeric dichlorobenzene in the increasing order of their boiling point and melting points.

Arrange the decreasing order of pKb values.

\[\ce{C6H5NH2, C6H5NHCH3, C6H5CH2NH2, CH3NH2, NH3}\]

Calculate the half-life of a first order reaction from the rate constant given below:

2 min⁻¹

Calculate the half-life of a first order reaction from the rate constant given below:

4 year⁻¹

A first order reaction takes 40 min for 30% decomposition. Calculate t_1/2.

Give a simple chemical test to distinguish between the following pair of compounds:

Ethanal and Propanal

Write the structure of an isomer of compound C₄H₉Br which is most reactive towards S_N1 reaction