Chemistry
How would you obtain:
(a) a base from another base,
(b) an alkali from a base,
(c) salt from another salt?
Answer
(a) A base from another base can obtained by double decomposition. The aqueous solution of salts with base (alkali) precipitates the respective metallic hydroxide.
For example,
FeCl3 + 3NaOH ⟶ 3NaCl + Fe(OH)3 ↓ [red brown ppt.]
(b) An alkali from a base can be obtained by the action of water on soluble metallic oxides like oxides of sodium, potassium and calcium:
CaO + H2O ⟶ Ca(OH)2
(c) A salt from another salt can be obtained by adding an alkali to the solutions of the salts of the heavy metals like copper, iron, zinc, etc.
For example,
FeSO4 [aq.] + 2NaOH [aq.] ⟶ Na2SO4 [aq.] + Fe(OH)2 ↓ [dirty green]
Related Questions
HCl, HNO3, C2H5OH, C6H12O6 all contain H atoms but only HCl and HNO3 show acidic character. Why?
(a) Dry HCl gas does not change the colour of dry litmus paper. Why?
(b) Is PbO2 a base or not? Comment.
(c) Do basic solutions also have H+(aq.) ? Explain why are they basic by taking an example?
Write balanced equation to satisfy each statement.
(a) Acid + Active metal ⟶ Salt + Hydrogen
(b) Acid + Base ⟶ Salt + Water
(c) Acid + carbonate or bicarbonate ⟶ Salt + water + carbon dioxide
(d) Acid + sulphite or bisulphite ⟶ Salt + water + sulphur dioxide
(e) Acid + sulphide ⟶ Salt + hydrogen sulphide
The skin has and needs natural oils. Why it is advisable to wear gloves while working with strong alkalis?