(a)(i) Give the reason why copper turnings dissolve in AgNO\(_3\) solution but remain insoluble in Pb(NO\(_3\) )\(_2\) solution.
(ii) Copper turnings of mass 1.06g were placed in 250 cm\(^3\) of 0.20 mol dm\(^{-3}\) AgNO\(_3\). Calculate the amourt of silver ions present. [Cu = 63.5]
(iii) Determine whether all the copper in (a)(ii) above will discolvo in the solution. The equation for the reaction is CU\(_{(S)}\) + 2Ag\(^+_{(aq)}\) –> Ag\(_{(aq)}\) + Cu\(^{2+}_{(aq)}\)
(b)(i) List cheicil properties of acids
(ii) Give two large scale uses of HNO\(_3\)
(iii) Write an equation for the action of heat on each of the following compounds: I. Pb(NO\(_3\))\(_2\)
Il. AgNO\(_3\).
(c)(i) State what would be observed if a piece of damp blue litmus paper is dropped into a glass jar of chlorine.
(ii) Name the type of reaction which occurs in (c)(i) above.
(iii) Give the property of chlorine which is exhibited in the reaction in (c)(i) above.
(i) Name two products obtained directly from the destructive distillation of coal.
(ii) Give one use of each product named in (d)(i) above.
Explanation
(a)(i) Copper is more reactive than silver or copper is higher in the electrochemical series than silver. Hence it will displace silver ions from solution. Copper, being less reactive than lead cannot displace lead, henc it remains insoluble in Pb(NO\(_3\))\(_{2(aq)}\).
(ii) No. of mole of Ag\(^+\) in the solution.
\(\frac{250cm^3 \times 0.2}{1000}\) mole Ag\(^+\) = 0.05mole;
Cu + 2Ag+ 2Ag\(^+\) \(\to\) 2Ag\(^+\) + Cu\(^{2+}\)
63.5g Cu dissolves in 2 mole Ag\(^+\)
1.06g Cu will dissolve in \(\frac{2 \times 1.06}{63.5}\) mol Ag\(^+\) = 0.033
(iii) Amount of (Ag\(^+\)) silver ion present = 0.05. Since this is more than the amount required (0.033) i.e. the AgNO\(_{3(aq)}\) is in excess, all the copper turnings will dissolve
(b)(i) Acids react with electropositive metals to liberate hydrogen
(ii) Acids neutralize bases to form salts.
(iii) Acids react with trioxocarbonate (IV) salts to liberate CO\(_{2(g)}\)
(iv) Acid react with trioxosulphate (IV) salts to liberate SO\(_2\)
(ii) Large scale uses of HNO\(_3\) (1) For manufacturing nitrocompounds such as nitrocellulose which is used for making artificial silk, explosives or compounds for manufacturing dyes. (2) For manufacturing fertilizer. (3) As an oxidizing agent. (4) rocket fuel.
(iii) 2Pb(NO\(_3\))\(_{2(s)}\) \(\to\) 2PbO\(_{(s)}\) + 4NO\(_{2(g)}\) + O\(_{2}\) -
2AgNO\(_{3(s)}\) -> 2Ag\(_{(s)}\) + 2NO\(_{2(g)}\) + O\(_{2(g)}\)
(c)(i) The litmus paper turns pink or red and then white or bleached. (ii) Redox reaction (iii) Bleachinc agent
(d)(i) Coke, coal tar, coal gas and ammoniacal liquor
(ii) uses Coke - a reducing agent or used as fuel.
Coal tar -in manufacture of drugs, dyes, explosives.
Coal gas - as fuel. Ammoniacal liquor -manufacture of fertilizer.