Answer : The correct option for blank 1 is, Shifts left.
The correct option for blank 2 is, Reverse.
Explanation :
According to the Le Chatelier's Principle, when the addition of the reactant in reaction system then the equilibrium will shift to the right (forward) direction of the reaction.
Or, if we remove the reactants from the reaction system then the equilibrium will be shifted to the left (backward) direction of the reaction. And simultaneously, there will be increase in the reverse reaction for the attainment of the equilibrium.
From other sources, the given mass of the solute that is being dissolved here is 7.15 g Na2CO3 - 10H2O. We use this amount to convert it to moles of Na2CO3 by converting it to moles using the molar mass then relating the ratio of the unhydrated salt with the number of water molecules. And by the dissociation of the unhydrated salt in the solution, we can calculate the moles of Na+ ions that are present in the solution.
Na2CO3 = 2Na+ + CO3^2-
7.15 g Na2CO3 - 10H2O (1 mol / 402.9319 g) (1 mol Na2CO3 / 1 mol Na2CO3 - 10H2O) ( 1 mol Na2CO3 / 1 mol Na2CO3-10H2O ) ( 2 mol Na+ / 1 mol Na2CO3) = 0.04 mol Na+ ions present
I think it's - log [H3O^+]
P.S. the 3 is a lowered exponent