Science (English Medium) Class 11 - CBSE Question Bank Solutions for Chemistry

\[\ce{K_{a_1}, K_{a_2}}\] and \[\ce{K_{a_3}}\] are the respective ionisation constants for the following reactions.

\[\ce{H2S ⇌ H^{+} + Hs-}\]

\[\ce{Hs- ⇌ H^{+} + S^{2-}}\]

\[\ce{H2S ⇌ 2H^{+} + S^{2-}}\]

The correct relationship between \[\ce{K_{a_1}, K_{a_2}}\] and \[\ce{K_{a_3}}\] is ______.

What will be the value of pH of 0.01 mol dm^–3 \[\ce{CH3COOH}\] (K_a = 1.74 × 10^–5)?

Assertion (A): The ionisation of hydrogen sulphide in water is low in the presence of hydrochloric acid.

Reason (R): Hydrogen sulphide is a weak acid.

Three students, Manish, Ramesh and Rajni were determining the extra elements present in an organic compound given by their teacher. They prepared the Lassaigne’s extract (L.E.) independently by the fusion of the compound with sodium metal. Then they added solid FeSO₄ and dilute sulphuric acid to a part of Lassaigne’s extract. Manish and Rajni obtained prussian blue colour but Ramesh got red colour. Ramesh repeated the test with the same Lassaigne’s extract, but again got red colour only. They were surprised and went to their teacher and told him about their observation. Teacher asked them to think over the reason for this. Can you help them by giving the reason for this observation. Also, write the chemical equations to explain the formation of compounds of different colours.

The equilibrium constant for a reaction is 10. What will be the value of ΔG^⊝? R = 8.314 JK^–1 mol^–1,T = 300 K.

Arrange the set of compound in order of their decreasing relative reactivity with an electrophile, E⁺ Chlorobenzene, 2,4-dinitrochlorobenzene, p-nitrochlorobenzene.

Arrange the set of compound in order of their decreasing relative reactivity with an electrophile, E⁺ Toluene, p-H₃C–C₆H₄–NO₂, p-O₂N–C₆H₄–NO₂.

Out of benzene, m–dinitrobenzene and toluene which will undergo nitration most easily and why?

Suggest the name of a Lewis acid other than anhydrous aluminium chloride which can be used during ethylation of benzene.

An organic compound contains 69% carbon and 4.8% hydrogen, the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20 g of this substance is subjected to complete combustion.

What is the pH of 0.001 M aniline solution? The ionization constant of aniline can be taken from Table 7.7. Calculate the degree of ionization of aniline in the solution. Also calculate the ionization constant of the conjugate acid of aniline

Calculate the degree of ionization of 0.05M acetic acid if its pK_a value is 4.74.

How is the degree of dissociation affected when its solution also contains

1. 0.01 M
2. 0.1 M in HCl?

The ionization constant of dimethylamine is 5.4 × 10^–4. Calculate its degree of ionization in its 0.02 M solution. What percentage of dimethylamine is ionized if the solution is also 0.1 M in NaOH?

Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:

Human muscle-fluid, 6.83

Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:

Human stomach fluid, 1.2

Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:

Human blood, 7.38

Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:

Human saliva, 6.4.

A 0.02 M solution of pyridinium hydrochloride has pH = 3.44. Calculate the ionization constant of pyridine.

Use the molecular orbital energy level diagram to show that \[\ce{N2}\] would be expected to have a triple bond, \[\ce{F2}\], a single bond and \[\ce{Ne2}\], no bond.

At 298 K. K_p for the reaction \[\ce{N2 O4 (g) ⇌ 2NO2 (g)}\] is 0.98. Predict whether the reaction is spontaneous or not.