The solubility of a salt of weak acid $$(AB)$$ at $$pH\,$$ $$3$$ is $$Y \times {10^{ - 3}}$$ $$mol\,{L^{ - 1}}.$$ The value of $$Y$$ is ________________.

(Given that the value of solubility product of $$AB$$ $$\left( {{K_{sp}}} \right) = 2 \times {10^{ - 10}}$$ and the value of ionization constant of $$HB$$ $$\left( {{K_a}} \right) = 1 \times {10^{ - 8}}$$)

In 1 L saturated solution of AgCl [K_sp(AgCl) = 1.6 $$\times$$ 10^-10], 0.1 mol of CuCl [K_sp(CuCl) = 1.0 $$\times$$ 10^-6] is added. The resultant concentration of Ag⁺ in the solution is 1.6 $$\times$$ 10^-x. The value of "x" is

Amongst the following the total number of compounds whose aqueous solution turns red litmus paper blue is
KCN, K₂SO₄, (NH₄)₂C₂O₄, NaCl, Zn(NO₃)₂, FeCl₃, K₂CO₃, NH₄NO₃ and LiCN