Advertisements
Advertisements
प्रश्न
What do you observe when caustic soda solution is added to the following solution, first a little and then in excess:
ZnSO4
Write a balanced equation for this reaction.
Advertisements
उत्तर
\[\ce{\underset{\text{Colourless}}{ZnSO4} + 2NaOH -> \underset{\text{white gelatinous ppt.}}{Zn(OH)2↓} + \underset{\text{Colourless}}{Na2SO4}}\]
In excess of alkali , White gelatinous ppt. of Zn(OH)2 becomes soluble :
\[\ce{Zn(OH)2 + 2NaOH(excess) -> \underset{\text{Sodium Zincate (Colourless)}}{Na2ZnO2 + 2H2O}}\]
APPEARS IN
संबंधित प्रश्न
Identify the substance underlined, in the following case:
Cation that does not form a precipitate with ammonium hydroxide but forms one with sodium hydroxide.
Using sodium hydroxide solution, how will you distinguish:
Lead hydroxide from magnesium hydroxide.
Write equation for the reaction that will take place when copper sulphate solution is added to sodium hydroxide solution.
Three test tubes contain calcium nitrate solution, zinc nitrate solution and lead nitrate solution respectively. Each solution is divided into two portions (i) and (ii). Describe the effect of
- adding sodium hydroxide solution to each portion in turn till it is in excess.
- adding ammonium hydroxide to each portion in turn till it is in excess.
Write the observation, and balanced equation for the following reaction:
Sodium hydroxide is added dropwise to a solution of zinc sulphate, till it is in excess.
Using Sodium hydroxide solution, how would you distinguish: Iron(II) chloride from Iron (III) chloride
Sodium hydroxide solution is added first in a small quantity, then in excess to the aqueous salt solutions of copper (II) sulphate, zinc nitrate, lead nitrate, calcium chloride, and iron (III) sulphate. Copy the following table and write the colour of the precipitate in (i) to (v) and the nature of the precipitate (soluble or insoluble) in (vi) to (x).
| Aqueous salt solution | Colour of precipitate when NaOH is added in a small quantity | Nature of precipitate (soluble or insoluble) when NaOH is added in excess |
| Copper (II) sulphate | (i) | (vi) |
| Zinc nitrate | (ii) | (vii) |
| Lead nitrate | (iii) | (viii) |
| Calcium chloride | (iv) | (ix) |
| Iron (III) Sulphate | (v) | (x) |
Sodium hydroxide solution is added to the solutions containing the ions mentioned in List X. List Y gives the details of the precipitate. Match the ions with their coloured precipitates.
| List X | List Y |
| (i) Pb2+ | (A) Reddish Brown |
| (ii) Fe2+ | (B) White insoluble inexcess |
| (iii) Zn2+ | (C) Dirty green |
| (iv) Fe3+ | (D) White soluble in excess |
| (v) Cu2+ | (E) White soluble in excess |
| (vi) Ca2+ | (F) Blue |
Distinguish by adding:
Sodium hydroxide solution and ammonium hydroxide solution to calcium salt solution and lead salt solution.
Aqueous lead (II) nitrate can be distinguished from aqueous zinc nitrate by adding any of the following solutions in excess, except:
