Careers360 -

Go To Your Study Dashboard

8.1 Assign oxidation number to the underlined elements in each of the following species

$(a) NaH_{2}\bar{P}O_{4}$

$(b)NaH\bar{S}O_{4}$

$(c) H_{4}\bar{P_{2}}O_{7}$

$(d) K_{2}\bar{Mn}O_{4}$

$(e) Ca\bar{O_{2}}$

$(f) Na\bar{B}H_{4}$

$(g) H_{2}\bar{S_{2}}O_{7}$

$(h) KAl(\bar{S}O_{4})_{2}.12H_{2}O$

8.2 What are the oxidation number of the underlined elements in each of the following and how do you rationalize your results

$(a) K\underline{I}_{3}$

$(b) H_{2}\underline{S_{4}}O_{6}$

$(c) \underline{Fe}_{3}O_{4}$

$(d) \underline{C}H_{3}\underline{C}H_{2}OH$

$(e) \underline{C}H_{3}\underline{C}OOH$

8.3 Justify that the following reactions are redox reactions:

$(a) CuO_{(s)}+H_{2}_{(g)}\rightarrow Cu_{(s)}+ H_{2}O_{(g)}$

8.3 Justify that the following reactions are redox reactions:

(b) $Fe_{2}O_{3}_{(s)}+3CO \rightarrow 2Fe_{(s)}+3CO_{2}_{(g)}$

8.3 Justify that the following reactions are redox reaction

(c) $4BCl_{3}_{(g)}+3LiAlH_{4}_{(s)}\rightarrow 2B_{2}H_{6}_{(g)}+3LiCl_{(s)}+3AlCl_{3}_{(s)}$

8.3 Justify that the following reactions are redox reaction

(d) $2K_{(s)}+F_{2}_{(g)}\rightarrow 2K^{+}F^{-}_{(s)}$

8.3 Justify that the following reactions are redox reaction

(e) $4NH_{3}_{(g)}+5O_{2}_{(g)}\rightarrow4NO_{(g)}+6H_{2}O_{(g)}$

8.4 Fluorine reacts with ice and results in the change

$H_{2}O_{(s)}+F_{2}_{(g)}\rightarrow HF_{(g)}+HOF_{(g)}$

Justify that this reaction is a redox reaction

8.5 Calculate the oxidation number of sulphur, chromium, and nitrogen in $H_{2}SO_{5}$ , $Cr_{2}O_{7}^{2-}$ and $NO_{3}^{-}$ . Suggest the structure of these compounds. Count for the fallacy.

8.6 Write formulas for the following compounds:

(a) Mercury(II) chloride

8.6 Write formulas for the following compounds:

(b) Nickel(II) sulphate

8.6 Write formulas for the following compounds:

(c) Tin(IV) oxide

8.6 Write formulas for the following compounds:

(d) Thallium(I) sulphate

8.6 Write formulas for the following compounds:

(e) Iron(III) sulphate

8.6 Write formulas for the following compounds:

(f) Chromium(III) oxide

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

8.8 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?

8.9 Consider the reactions:
$(a) 6CO_{2}_{(g)}+6H_{2}O_{(l)}\rightarrow C_{6}H_{12}O_{6}_{(aq)}+6CO_{2}_{(g)}$

$(b) O_{3}_{(g)}+H_{2}O_{2}_{(l)}\rightarrow H_{2}O(l) +2O_{2}(g)$
Why it is more appropriate to write these reactions as :

$(a) 6CO_{2}_{(g)}+12H_{2}O_{(l)}\rightarrow C_{6}H_{12}O_{6}_{(aq)}+6H_{2}O_{(l)}+6CO_{2}_{(g)}$

$(b) O_{3}_{(g)}+H_{2}O_{2}_{(l)}\rightarrow H_{2}O(l) +O_{2}(g)+O_{2}_{(g)}$

Also, suggest a technique to investigate the path of the above (a) and (b) redox reactions.

8.10 The compound $AgF_{2}$ is unstable compound. However, if formed, the compound acts as a very strong oxidising agent. Why ?

8.11 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?

8.12 How do you count for the following observations?

(a) 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.

8.12: How do you count for the following observations?

(b) When concentrated sulphuric acid is added to an inorganic mixture containing chloride, we get the colourless, pungent smelling gas HCl, but if the mixture contains bromide then we get red vapour of bromine. Why ?

8.13 Identify the substance oxidised reduced, oxidising agent and reducing agent for each of the following reactions

$(a)2AgBr(s)+C_{6}H_{6}O_{2}(aq)\rightarrow 2Ag(s)+2HBr(aq)+C_{6}H_{4}O_{2}(aq)$

8.13 Identify the substance oxidised reduced, oxidising agent and reducing agent for each of the following reactions

$(b) HCHO(l)+2[Ag(NH_{3})]^+(aq) +3OH^-(aq)\rightarrow 2Ag(s)+HCOO^- (aq)+4NH_{3}(aq) +2H_{2}O(l)$

8.13 Identify the substance oxidised reduced, oxidising agent and reducing agent for each of the following reactions

$(c) HCHO(l)+2Cu^{+}(aq)+5OH^{-}(aq)\rightarrow Cu_{2}O(s)+HCOO^{-}(aq)+3H_{2}O$

Exams

Articles

Questions