The impurities in NaCI (Na₂ SO₄, MgCl₂, etc) will absorb moisture from air and makes it wet

Sodium hydrogen carbonate or sodium bicarbonate is used in baking cakes, pastries etc. It is so called because it decomposes on heating to generate bubbles of carbon dioxide, leaving holes in cakes or pastries and making them light and fluffy

(i) Sodium hydroxide is used as a laboratory reagent
(ii) It is also used in the purification of bauxite and petroleum refining
(iii) It is used in the textile industry for mercerising cotton fabrics
(iv) It is used in the manufacture of soap, paper, artificial silk and a number of chemicals

The acids in which the acidic proton is present on hydroxyl group with an oxo-group attached to the same atom is called oxo-acids.

The largest use of plaster of paris is in the building industry as well as plasters. It is used for immobilising the affected part of organ where there is a bone fracture or sprain. It is also employed in dentistry, in ornamental work and for making casts of statues and busts.

6Li + N₂ ⟶ 2Li₃ N

2NH₃ + H₂O + CO₂ ⟶ (NH₄)₂ CO₃
(NH₄)₂ CO₃ + H₂O + CO₂ ⟶ 2NH₄ HCO₃
2NH₄HCO₃ + NaCl ⟶ NH₄Cl + NaHCO₃
2NaH CO₃ ⟶ Na₂ CO₃ + CO₂ + H₂O.

The solubility product of NaCl is lower than that of NaOH. The more soluble a substance is, the higher the K_sp value it has In aqueous solution NaOH gives OH^- ions. It can be solvated by establishing H-bonds with water molecules. So it is more water soluble.

Mg (OH)₂ ; Magnesium hydroxide.

Magnesium oxide in having higher melting point. The lattice energy of MgO & MgF₂ are 3938 and 2957 respectively.
MgO has +2, -2 charges, MgF₂ has +2, -1 charges. When the two charges are multiplied together, MgO results in larger amount of lattice energy since it has a higher charge, The strong attraction cause most ionic material to be hard and brittle and have high melting points.