An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved. 

Explanation

`A-Na, B-Cl_2,C-NaCl,D-NaOH`
`2Na+Cl_2 to 2NaCl`
`2NaCl (aq)+2H_2O(l) to 2NaOH (aq)+Cl_2(g)+H_2(g)`