Question

Read the following and answer any 4 from (i) to(v) (4)

A man went door to door posing as a goldsmith He promised to bring back the glitter

of the old and dull gold ornaments .An unsuspecting lady gave a set of gold bangles to him

which he dipped in a particular solution .The bangles sparkled like new but their weight was

reduced drastically.The lady was upset but after a futile argument the man beat a hasty

retreat

(i) Identify the nature of the solution used by the goldsmith.

(ii) Write the composition of the solution used.

(iii) Gold is used for making jewellery. Give reason.

(iv) What happens when gold is dipped in hot water ? Mention the reason for the

observation.

(v) Name 2 most malleable metals .​

Answer 1

Answer:

The man had used the solution of aqua-regia is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a yellow-orange fuming liquid. Aqua regia was so named because it can dissolve the noble metals gold and platinum. After dipping the gold ornaments in it the outer layer of gold gets dissolved and the inner shiny layer appears.