The formulas of A and B for the following reaction sequence

are

Find out the major product for the above reaction.

2L of 0.2M H₂SO₄ is reacted with 2L of 0.1M NaOH solution, the molarity of the resulting product Na₂SO₄ in the solution is _________ millimolar. (Nearest integer)

Metal $$\mathrm{M}$$ crystallizes into a fcc lattice with the edge length of $$4.0 \times 10^{-8} \mathrm{~cm}$$. The atomic mass of the metal is ____________ $$\mathrm{g} / \mathrm{mol}$$. (Nearest integer)

$$\left(\right.$$ Use : $$\mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{~mol}^{-1}$$, density of metal, $$\mathrm{M}=9.03 \mathrm{~g} \mathrm{~cm}^{-3}$$ )