Question

Calcium sulphate is found in nature in two forms, anhydrous calcium sulphate and hydrated calcium sulphate is heated with coke, sulphur dioxide gas is obtained. When hydrated calcium sulphate is heated at ${200}^{o}C$, it forms anhydrous salt.

When calcium sulphate is mixed with conc. $HCl$ and the paste is formed. What colour is obtained when a pinch of this paste is brought near the flame?

• A. golden yellow
• B. brick red
• C. crimson red
• D. apple green

Answer 1

The correct option is B brick red

When calcium sulphate is mixed with conc. HCl the paste is formed. When this paste is brought near the flame, brick red colour is obtained which is the characteristic colour of calcium.

Golden yellow is the characteristic colour of sodium.

Crimnson red is the characteristic colour of strontium.

Apple green is the characteristic colour of barium.