Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions for Chemistry

Which one of the alkaline earth metal carbonates is thermally the most stable?

What do you understand by electron-rich compounds of hydrogen? Provide justification with a suitable example.

What characteristics do you expect from an electron-deficient hydride with respect to its structure and chemical reactions?

Do you expect the carbon hydrides of the type (C_nH_{2n + 2}) to act as ‘Lewis’ acid or base? Justify your answer.

Arrange the following:

LiH, NaH and CsH in order of increasing ionic character.

Calculate the oxidation number of sulphur, chromium and nitrogen in H₂SO₅, `"Cr"_2"O"_7^(2-)` and `"NO"_3^-`. Suggest structure of these compounds. Count for the fallacy.

Consider the reaction:

\[\ce{O3(g) + H2O2(l) → H2O(l) + 2O2(g)}\]

Why it is more appropriate to write these reaction as:

\[\ce{O3(g) + H2O2 (l) → H2O(l) + O2(g) + O2(g)}\]

Also, suggest a technique to investigate the path of the redox reactions.

The compound AgF₂ is an unstable compound. However, if formed, the compound acts as a very strong oxidizing agent. Why?

Whenever a reaction between an oxidising agent and a reducing agent is carried out, a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement giving three illustrations.

How do you count for the following observations?

Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in the manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant. Why? Write a balanced redox equation for the reaction.

Balance the following redox reactions by ion-electron method:

1. \[\ce{MnO-_4 (aq) + I– (aq) → MnO2 (s) + I2(s) (in basic medium)}\]
2. \[\ce{MnO-_4 (aq) + SO2 (g) → Mn^{2+} (aq) + HSO-_4  (aq) (in acidic solution)}\]
3. \[\ce{H2O2 (aq) + Fe^{2+} (aq) → Fe^{3+} (aq) + H2O (l) (in acidic solution)}\]
4. \[\ce{Cr_2O^{2-}_7 + SO2(g) → Cr^{3+} (aq) + SO^{2-}_4 (aq) (in acidic solution)}\]

Balance the following equation in basic medium by ion-electron method and oxidation number methods and identify the oxidising agent and the reducing agent.

\[\ce{P4(s) + OH–(aq) —> PH3(g) + HPO^–_2(aq)}\]

Balance the following equation in the basic medium by ion-electron method and oxidation number methods and identify the oxidising agent and the reducing agent.

\[\ce{N2H4(l) + ClO^-_3 (aq) → NO(g) + Cl–(g)}\]

Balance the following equation in basic medium by ion-electron method and oxidation number methods and identify the oxidising agent and the reducing agent.

\[\ce{Cl_2O_{7(g)} + H_2O_{2(aq)} -> ClO-_{2(aq)} + O_{2(g)} + H+_{(aq)}}\]

The Mn³⁺ ion is unstable in solution and undergoes disproportionation to give Mn²⁺, MnO₂, and H⁺ ion. Write a balanced ionic equation for the reaction.

Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. Present a balanced equation for this redox change taking place in water.

In Ostwald’s process for the manufacture of nitric acid, the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained starting only with 10.00 g. of ammonia and 20.00 g of oxygen?

What do you understand by electron-deficient? Provide justification with a suitable example.

What do you understand by electron-precise? Provide justification with a suitable example.

Consider the reaction:

\[\ce{6 CO2(g) + 6H2O(l) → C6 H12O6(aq) + 6O2(g)}\]

Why it is more appropriate to write these reaction as:

\[\ce{6CO2(g) + 12H2O(l) → C6 H12O6(aq) + 6H2O(l) + 6O2(g)}\]

Also, suggest a technique to investigate the path of the redox reactions.