1. The mass of the solution is V*d, so the mass of sodium hydroxide is V * D * W.

So the number of moles of sodium hydroxide is V*d*W/40.

So the molar concentration of sodium hydroxide is d*W/40.

After dilution, the concentration becomes d*W*(V-m)/(V*40).

When diluted, the concentration becomes d * w * [(v-m)/v] 2/40.

The molar number of sodium hydroxide is d * w * (v-m) 2/(v * 40).

Neutralization requires the same molar amount of hydrochloric acid.

The mass of hydrochloric acid is d * w * (v-m) 2 * 36.5/(v * 40).

The mass of hydrochloric acid solution is d * w (v-m) 2 * 36.5/4v.

2. The first three are composed of the same elements, but not the same substance.

The latter three are different generic names of the same substance.