Assign oxidation numbers to the underlined elements in each of the following species: (a) NaH₂PO₄ (b) NaHSO₄ (c) H₄P₂O₇ (d) K₂MnO₄(e) CaO2 (f) NaBH4 (g) H2S2O7 (h) KAl(SO4)2.12 H2O

What are the oxidation numbers of the underlined elements in each of the following and how do you rationalise your results?(a) KI3 (b) H2S4O6 (c) Fe3O4 (d) CH3CH2OH (e) CH3COOH

Justify that the following reactions are redox reactions: (a) CuO(s) + H₂(g) ? Cu(s) + H₂O(g) (b) Fe₂O₃(s) + 3CO(g) ? 2Fe(s) + 3CO₂(g) (c) 4BCl₃(g) + 3LiAlH₄(s) ? 2B₂H₆(g) + 3LiCl(s) + 3 AlCl₃ (s) (d) 2K(s) + F₂(g) ? 2K+F– (s) (e) 4 NH₃(g) + 5 O₂(g) ? 4NO(g) + 6H₂O(g)

Fluorine reacts with ice and results in the change: H₂O(s) + F₂(g) ? HF(g) + HOF(g)Justify that this reaction is a redox reaction.

Calculate the oxidationnumber ofsulphur, chromium and nitrogeninH₂SO₅, –. Suggest structure of these compounds. Count for the fallacy.

Write the formulae for the following compounds: (a)Mercury(II)chloride(b) Nickel(II)sulphate (c)Tin(IV)oxide(d) Thallium(I)sulphate(e) Iron(III) sulphate (f) Chromium(III) oxide

Suggest a list of the substances where carbon can exhibit oxidation states from –4 to +4 and nitrogen from –3 to +5.

While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?

Consider the reactions: (a) 6 CO₂(g) + 6H₂O(l) ? C₆ H₁₂ O₆(aq) + 6O₂(g) (b) O₃(g) + H₂O₂(l) ? H₂O(l) + 2O₂(g) Why it is more appropriate to write these reactions as: (a) 6CO₂(g) + 12H₂O(l) ? C₆ H₁₂ O₆(aq) + 6H₂O(l) + 6O₂(g) (b) O₃(g) + H₂O₂ (l) ? H₂O(l) + O₂(g) + O₂(g) Also suggest a technique to investigate the path of the above (a) and (b) 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? (I) 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 thereaction. (II) When concentrated sulphuric acid is added to an inorganic mixture containing chloride, we get colourless pungent smelling gas HCl, but if the mixture contains bromide then we get red vapour of bromine. Why?

Identify the substance oxidised, reduced, oxidising agent and reducing agent for each of the following reactions: (a) 2AgBr (s) + C₆H₆O₂(aq) ? 2Ag(s) + 2HBr (aq) + C₆H₄O₂(aq) (b) HCHO(l) + 2[Ag (NH₃)₂]⁺(aq) + 3OH^–(aq) ? 2Ag(s) + HCOO^–(aq) + 4NH₃(aq) + 2H₂O(l) (c) HCHO (l) + 2Cu²⁺⁽aq) + 5 OH^–(aq) ? Cu₂O(s) + HCOO^–(aq) + 3H₂O(l) (d) N₂H₄(l) + 2H₂O₂(l) ? N₂(g) + 4H₂O(l) (e) Pb(s) + PbO₂(s) + 2H₂SO₄(aq) ? 2PbSO₄(s) + 2H₂O(l)

Consider the reactions: (aq) +I₂(s) ?(aq) +2I^–(aq) aq) + 2Br₂(l) + 5H₂O(l)?(aq) + 4Br^–(aq) +10H⁺(aq) Why does the same reductant, thiosulphate react differently with iodine and bromine?

Justify giving reactions that among halogens, fluorine is the best oxidant and among hydrohalic compounds, hydroiodic acid is the best reductant.

Why does the following reaction occur? (aq) + 2F^– (aq) + 6H⁺(aq) ? XeO₃(g) + F₂(g) + 3H₂O(l) What conclusion about the compound Na₄XeO₆(ofwhichis a part) can be drawn from thereaction.

Consider the reactions: (I) H₃PO₂(aq) + 4 AgNO₃(aq) + 2 H₂O(l) ? H₃PO₄(aq) + 4Ag(s) +4HNO₃(aq) (II) H₃PO₂(aq) + 2CuSO₄(aq) + 2 H₂O(l) ? H₃PO₄(aq) + 2Cu(s) +H₂SO₄(aq) (c) C₆H₅CHO(l) + 2[Ag (NH₃)₂]⁺(aq) + 3OH^–(aq) ? C₆H₅COO^–(aq) + 2Ag(s) + 4NH₃ (aq) + 2 H₂O(l) (d) C₆H₅CHO(l) + 2Cu²⁺⁽aq) + 5OH^–(aq) ? No change observed.What inference do you draw about the behaviour of Ag+ and Cu2+ from these reactions?

Balance the following redox reactions by ion-electron method: (I) (aq) + I^– (aq) ? MnO₂ (s) + I₂(s) (in basicmedium) (II) (aq) + SO₂ (g) ? Mn²⁺ (aq) + (aq) (in acidicsolution) (III) H₂O₂ (aq) + Fe²⁺ (aq) ? Fe³⁺ (aq) + H₂O (l) (in acidicsolution) (d)+ SO₂(g) ? Cr³⁺(aq) +(aq) (in acidicsolution)

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

What sorts of informations can you draw from the following reaction ?

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

Consider the elements: Cs, Ne, I and F (I) Identify the element that exhibits only negative oxidationstate. (II) Identify the element that exhibits only postive oxidationstate. (III) Identify the element that exhibits both positive and negative oxidationstates. (IV) Identify the element which exhibits neither the negative nor does the positive oxidationstate.

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.

Refer to the periodic table given in your book and now answer the following questions: (I) Select the possible non metals that can show disproportionationreaction. (II) Select three metals that can show disproportionation reaction.

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?

Using the standard electrode potentials given in the Table 8.1, predict if the reaction between the following is feasible: (I) Fe³⁺(aq) andI^–(aq) (II) Ag⁺(aq) andCu(s) (III) Fe³⁺ (aq) andCu(s) (IV) Ag(s) andFe³⁺(aq) (V) Br₂(aq) andFe²⁺(aq)

Predict the products of electrolysis in each of the following: (I) An aqueous solution of AgNO₃ with silverelectrodes (II) An aqueous solution AgNO₃ with platinumelectrodes (III) A dilute solution of H₂SO₄ with platinumelectrodes (IV) An aqueous solution of CuCl₂ with platinumelectrodes.

Arrange the following metals in the order in which they displace each other from the solution of their salts.Al, Cu, Fe, Mg and Zn.

Given the standard electrode potentials, K⁺/K = –2.93V, Ag⁺/Ag = 0.80V, Hg²⁺/Hg = 0.79V Mg²⁺/Mg = –2.37V. Cr³⁺/Cr = –0.74VArrange these metals in their increasing order of reducing power.

Depict the galvanic cell in which the reaction Zn(s) + 2Ag⁺(aq) ? Zn²⁺(aq) + 2Ag(s) takes place, further show: (I) which of the electrode is negativelycharged, (II) the carriers of the current in the cell,and (III) individual reaction at each electrode.