Question

1)why does brass react with dilute hydrochloric acid and is corroded in rainy season to form CaCo3.
Cu(OH)2 ?
2) In an experiment,a student mixed the bertain cmount of aqueous solution of sodium sulphate with barium chloride. write c.r.

Answer 1

Brass is an alloy of copper and zinc.The metals Cu and Zn in brass react with dil. hydrochloric acid to form Cu(II) and Zn(II) compounds.  

In rainy season, brass gets corroded because copper in brass reacts with oxygen, carbon dioxide and moisture present in the atmosphere to form basic copper carbonate.

2Cu + O2 + CO2 + H2O → CuCO3.Cu(OH)2