I'm just taking a self educated guess of A sorry if I'm wrong :C
Impossible to form from given reactants
Explanation:
Only sodium has carbonate ion here .so only possible way to displace carbonate is to use potassium
When sodium carbonate and Potassium iodide react with each other double displacement reaction occurs
As potassium is powerful than sodium it displaces sodium to form potassium carbonate .
Then you have to use water and then you can use calcium suppliment .
Explanation:
According to Le Chatelier's principle, any disturbance caused in an equilibrium reaction will shift the equilibrium in a direction that will oppose the change.
As the given reaction is as follows.

(a) When increase the temperature of the reactants or system then equilibrium will shift in forward direction where there is less temperature. It is possible for an endothermic reaction.
Thus, formation of
will increase.
- (b) When we decrease the volume (at constant temperature) of given reaction mixture then it implies that there will be increase in pressure of the system. So, equilibrium will shift in a direction where there will be decrease in composition of gaseous phase. That is, in the backward direction reaction will shift.
Hence, formation of
will decrease with decrease in volume.
- When we increase the mount of
then equilibrium will shift in the direction of decrease in concentration that is, in the forward direction.
Thus, we can conclude that formation of
will increase then.
Snow tends to accumulate better on grass surfaces than concrete surfaces for several reasons. (1) A road surface is connected directly to the earth's surface. Vegetation and grass is more exposed to the cold air. It takes time for the soil temperatures do adjust to colder air temperatures.