On heating quick lime with coke in an electric furnace,we get

Which of the following is insoluble in excess of $NaOH$?

Which of the following compounds has a negative enthalpy of solution?

Which of the following statements is incorrect?

Sodium is heated in air at $300^{\circ} C$ to form $X$. $X$ absorbs $CO_2$ and forms $Na_2CO_3$ and $Y$. Which of the following is $Y$?

The function of "Sodium pump" is a biological process operating in each and every cell of all animals. Which of the following biologically important ions is also a constituent of this pump?