(a) List two gases in each case which;
(i) can be used to demonstrate the fountain experiment;
(ii) decolourize acidified potassium tetraoxomanganate (VII).
(b) State briefly how you would distinguish between
(i) crystals of PbCO\(_3\) and Pb(NO\(_3\)) using heat;
(ii) solutions of NH\(_4\)CI and NaCl using litmus paper.
(c) Mention two changes that would be observed on adding moderately concentrated hydrochloric acid to iron filings
Explanation
(a)(i) NH\(_3\) or HCl or SO\(_2\) (any two)
(i) H\(_2\)S, SO\(_2\), C\(_2\)H\(_4\), C\(_2\)H\(_2\) etc.(any two)
(b)(i) On heating PbCO\(_3\) decomposes giving a colourless, odourless gas
- and yellow residue Pb(NO\(_3\))\(_2\) decomposes giving brown fumes and yellow residue.
(ii) BH\(_4\)Cl\(_{(aq)}\) turns blue litmus paper red NaCl\(_{(aq)}\) has no effect on litmus paper
(c) Effervescence/gas evolved. Green solution or gas evolved, iron filings dissolved to give a green solution