Question

Give reasons for the following: (i) Gold and silver are used for jewellery making. (ii) carbonate and sulphide ores are usually converted into oxides prior to reduction during the process of extraction

Answer 1

i) Gold and silver are used for jewellery making because these are lustrous (shiny) metals.
ii) Carbonate and sulphide ores are usually converted into oxides prior to reduction during the process of extraction because oxides are easy to reduce than carbonates and sulphides.

Answer 2

1) Gold and Silver are used for making jewellery because they hardly react with water that 's why they didn 't get rust and they look superior they are not destroyed by chemical reaction...

or

Gold and silver are used to make jewellery because they are precious and expensive metals. Also, gold and silver last very long and look luxurious.

2) Conversion of concentrated ore into metal oxide 

It is easier to obtain metals from their oxides rather than from carbonates or sulphides. So the ore is first converted into an oxide. A carbonate ore is first converted into oxide ore by calcination. A sulphide ore is converted into oxide ore by roasting.