Question #c8734

1 Answer
Apr 24, 2016

Answer:

#"Option B"#

Explanation:

Water undergoes autoprotolysis under standard conditions. What does this mean? It means that the water molecule undergoes the following equilibrium where an #O-H# bond is broken:

#2H_2O rightleftharpoons H_3O^(+) + HO^(-)#

This is an equilibrium reaction, which can certainly be measured, but it measures #[H_3O^+]# and #[HO^-]# from all sources.

i.e. #K_w = [H_3O^+][HO^-]=10^-14#

Now sulfurous acid contributes to the equilibrium:

#H_2SO_3(aq) + H_2O(l) rarr HSO_3^(-) + H_3O^+#

Since we know that #[H_3O^+] =1xx10^-3#, #[HO^-]=K_w/[[H_3O^+]]# #=# #10^-11*"mol"*L^-1#