(a) Copper powder is taken in a china dish and heated over a burner. Name the product formed and state its colour. Write the chemical equation for the reaction involved. OR (b) Write chemical equation for the chemical reaction which occurs when the aqueous solutions of barium chloride and sodium sulphate react together. Write the symbols of the ions present in the compound precipitated in the reaction.

(a) When copper powder is heated in a china dish over a burner, the product formed is copper(II) oxide. The colour of the product is black. The chemical equation for the reaction involved is: $$2Cu + O_2 ightarrow 2CuO$$ OR (b) The chemical equation for the reaction between aqueous solutions of barium chloride and sodium sulphate is: $$BaCl_2 + Na_2SO_4 ightarrow BaSO_4 + 2NaCl$$ The symbols of the ions present in the compound precipitated in the reaction are: $$Ba^{2+}$$ and $$SO_4^{2-}$$