Why the alkali is added drop by drop to the salt solution?

Write balanced equation:

(a) Reaction of sodium hydroxide solution with Iron (III) chloride solution

(b) Copper sulphate solution with ammonium hydroxide solution

The colour of the precipitate formed on adding NaOH solution to iron (II) sulphate solution is:

1. White
2. Brown
3. Green
4. Pale blue

A metal which produces hydrogen on reacting with alkali as well as with acid:

1. Iron
2. Magnesium
3. Zinc
4. Copper