Answer:
2.19 x 10^-12.
Explanation:-
The relation between Ka and Kb for an acid and it's conjugate base is
Ka x Kb = Kw where Kw = ionic product of water.
So Kb = 10^-14 / (4.57 x 10 ^ -3)
= 2.19 x 10^-12
<span>Double displacement reaction is your answer.</span>
The the last one, but isn't it c6h12o6?
Always use least amount of sig figs possible. So this 9.7 would be (answer): 2 sig figs