`CO_2` is inert and harmless gas, yet it is thought to be a serious pollutant. Explain.

CO2 is inert and harmless gas, yet it is thought to be a serious pollutant. Explain

A is a compound of calcium. On heating A a colourless gas B and a resides C are formed. When C is dissolved in water a compound D is obtained. When excess CO_2 is passed through the aqueous solution of D, E is formed. E on gentle heating gives A. Identify A, B, C and E.

Water is liquid while H_2S is a gas. Suggest reason for the above fact. Explain the phenomenon.

[Co(NH_3)_6]^3+ is an inner orbital complex whereas [Ni(NH_3)_6]^(2+) is an outer orbital complex.Explain.

CO_ 2 is a gas but SiO_2 is a solid. Give reason.

Although both CO_2 and H_2O are triatomic molecules.,the shape of H_2O molecular is bent while that of CO_2 is linear. Explain these on the basis of dipole moment.