Question

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 solutions of product C on electrolysis gives a compound D and liberates hydrogen. Identify A,B,C,D and write down the equation for the reaction involved

Answer 1

The element A is sodium (Na) metal as sodium burns with golden flame. The element B is Chlorine (Cl) as its atomic number is 17. Sodium reacts with chlorine to sodium chloride (NaCl). Therefore product (C) is NaCl. The reaction is shown as follows

2Na (s) + Cl₂ (g) -------> 2NaCl (s)

When an aqueous solution of sodium chloride is electrolysed, Chlorine is liberated at the anode and hydrogen is liberated at the cathode. The overall reaction of electrolysis is shown as follows

NaCl (aq) + H₂O (l) ---------> Na⁺(aq) + OH^-(aq) + 1/2 H₂(g) + 1/2 Cl₂(g)

Thus the product D is Chlorine gas (Cl₂).