White phosphorous catches fire in air to produce dense white fumes. This is due to the formation of

White phosphorous (P_4) has :

Calcium phosphide reacts with water or dil. HCl and give a compound 'X', which fails to react with HCl but produces dense white fumes with HI (g) due to formation of 'Y'. Compound X and Y respectively

Assertion : White phosphorus is more reactive than red phosphorus. Reason : It readily catches fire in air to give dense white fumes of P_(4)O_(10) .

Assertion : White phosphorus is more reactive than red phosphorus. Reason : It readily catches fire in air to give dense white fumes of P_(4)O_(10) .