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

Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.

Will CCl₄ give white precipitate of AgCl on heating it with silver nitrate? Give reason for your answer.

Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract for testing sulphur by lead acetate test?

In Lassaigne’s test for nitrogen in an organic compound, the Prussian blue colour is obtained due to the formation of ______.

The ionization constant of HF, HCOOH and HCN at 298K are 6.8 × 10^–4, 1.8 × 10^–4 and 4.8 × 10^–9 respectively. Calculate the ionization constants of the corresponding conjugate base.

The ionization constant of phenol is 1.0 × 10^–10. What is the concentration of phenolate ion in 0.05 M solution of phenol? What will be its degree of ionization if the solution is also 0.01M in sodium phenolate?

The ionization constant of acetic acid is 1.74 × 10^–5. Calculate the degree of dissociation of acetic acid in its 0.05 M solution. Calculate the concentration of acetate ion in the solution and its pH.

The ionization constant of chloroacetic acid is 1.35 × 10–3. What will be the pH of 0.1M acid and its 0.1M sodium salt solution?

Which of the following statement is not correct about the characteristics of cathode rays?

Which of the following order of energies of molecular orbitals of \[\ce{N2}\] is correct?

Which of the following statement is not correct from the view point of molecular orbital theory?

The energy of σ2p_z molecular orbital is greater than π2p_x and π2p_y molecular orbitals in nitrogen molecule. Write the complete sequence of energy levels in the increasing order of energy in the molecule. Compare the relative stability and the magnetic behaviour of the following species :

\[\ce{N2, N^{+}2, N^{-}2, N^{2+}2}\]

Which of the following molecular orbitals has maximum number of nodal planes?

In which of the following molecules, `σ2p_z` molecular orbital is filled after `π2p_x` and `π2p_y` molecular orbitals?

\[\ce{K_{a_1}, K_{a_2}}\] 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.