• The process of heating salt may dissociate the salt to release a certain type of gas.
• The gas can be identified through several tests as below:

• Lights up a glowing wooden splinter

• Produces a ‘pop’ sound with a lighted wooden splinter

• Turns limewater cloudy

• Turns a moist red litmus paper blue
• Produces thick white fumes with hydrogen chloride gas

• Bleaches a moist red litmus paper
• Turns a moist blue litmus paper red, then bleaches it

• Produces thick white fumes with ammonia gas

• Turns a moist blue litmus paper red

• Decolourises an acidified potassium manganate(VII) solution

• Turns the white anhydrous copper(II) sulphate blue
• Turns the blue cobalt(II) chloride paper pink

 Salts of \(Ca^{2+}, Mg^{2+}, Al^{3+}, Pb^{2+}, NH_4\,^{+}\)

 \(CuSO_4\), \(Cu(NO_3)_2\)

 \(CuCl_2\)

 Salts of ion ferum(II), \(Fe^{2+}\)

 Salts of ion ferum(III), \(Fe^{3+}\)

• The process of heating salt may dissociate the salt to release a certain type of gas.
• The gas can be identified through several tests as below:

• Lights up a glowing wooden splinter

• Produces a ‘pop’ sound with a lighted wooden splinter

• Turns limewater cloudy

• Turns a moist red litmus paper blue
• Produces thick white fumes with hydrogen chloride gas

• Bleaches a moist red litmus paper
• Turns a moist blue litmus paper red, then bleaches it

• Produces thick white fumes with ammonia gas

• Turns a moist blue litmus paper red

• Decolourises an acidified potassium manganate(VII) solution

• Turns the white anhydrous copper(II) sulphate blue
• Turns the blue cobalt(II) chloride paper pink

 Salts of \(Ca^{2+}, Mg^{2+}, Al^{3+}, Pb^{2+}, NH_4\,^{+}\)

 \(CuSO_4\), \(Cu(NO_3)_2\)

 \(CuCl_2\)

 Salts of ion ferum(II), \(Fe^{2+}\)

 Salts of ion ferum(III), \(Fe^{3+}\)