$NaOH$ (solid) $+ CO \xrightarrow{200^\circ C} X$; product $X$ is

Which of the following statement$(s)$ is (are) correct?
$(i)$ $LiF$ is less soluble in water
$(ii)$ $NaCl$ is less ionic than $CsCl$
$(iii)$ Formation of alkali metal halide is an endothermic reaction

Which of the following chemicals,in addition to water,are used for the manufacture of $Na_2CO_3$ by the Solvay process?

Which element of group-$1$ has the highest hydration enthalpy? Why?

Which of the following statements is incorrect for alkali metals?

Why does lithium differ from other alkali metals?