Question

A is green amorphous solid which on strong heating decompose to form a black residue B and colourless, odourless acidic gas c which turns lime water milky. when dilute sulphuric acid is added to B a blue solution of salt D is formed. identify A, B, c and D​

Answer 1

A is green amorphous solid are a solution of a.b.c ,and ,d.

Answer 2

A- Copper carbonate

B- Copper oxide

C- Carbon dioxide

D- Copper sulphate

• The green amorphous solid is copper carbonate (CuCO3) which decomposes to form a black residue which is copper oxide (CuO) and colourless, odorless acidic carbon dioxide gas.
• Thus B is copper oxide.
• Carbon dioxide gas is responsible for turning lime water milky therefore gas C is carbon dioxide.
• When dilute sulphuric acid is added to copper oxide, it forms copper sulphate solution which is blue in color.