(a) sodium hydroxide solution and (b) Ammonium hydroxide solution to (i) Calcium salt solution and lead salt solution
Distinguish by adding:
(a) sodium hydroxide solution and
(b) Ammonium hydroxide solution to
(i) Calcium salt solution and lead salt solution
(ii) Lead salt solution and ferrous salt solution
(iii) copper salt solution and ferrous salt solution
(iv) Fe (II) salt solution and Fe (III) Salt solution
(v) Ferrous nitrate and lead nitrate
1 Answers
(a) Distinguish by adding Sodium hydroxide solution:
(i) Ca(NO3)2 + 2NaOHCa(OH)2 + 2NaNO3
On adding excess of NaOH, ppt. of Ca (OH)2 is sparingly soluble.
Pb(NO3)2 + 2NaOHPb(OH)2 + 2NaNO3
On adding excess of NaOH, ppt of Pb(OH)2 is soluble.
(ii) Pb(NO3)2 + 2NaOHPb(OH)2 + 2NaNO3
On adding excess of NaOH, ppt of Pb(OH)2is soluble.
ZnSO4 + 2NaOHZn(OH)2 + Na2SO4
With excess of NaOH, white gelatinous ppt. of Zn (OH)2 is soluble. So, these two cannot be distinguished by NaOH alone. However white ppt. of Pb (OH)2is readily soluble in acetic acid also.
(iii) CuSO4 + 2NaOHCu(OH)2 + Na2SO4
With excess of NaOH, alkali pale blue ppt of Cu (OH)2 is insoluble.
FeSO4 + 2NaOHFe(OH)2 + Na2SO4
With excess of NaOH, dirty green ppt. of Fe(OH)2 is insoluble.
(iv) FeSO4 + 2NaOHFe(OH)2 + NaSO4
With excess of NaOH, dirty green ppt of Fe (OH)2 is insoluble.
FeCl3 + 3NaOHFe(OH)3 + 3NaCl
With excess of NaOH, reddish brown ppt of Fe (OH)3 is insoluble.
(b) Distinguish by adding Ammonium hydroxide solution:
(i) On addition of NH4OH to calcium salts no precipitation of Ca (OH)2 occurs even with addition of excess of NH4OH because the concentration of OH-ions from ionization of NH4OH is so low that it cannot precipitate the hydroxide of calcium.
Pb(NO3)2 + 2 NH4OHPb(OH)2 + 2NH4NO3
On adding excess of NH4OH, chalky white ppt. of Pb (OH)2 is insoluble.
(ii) Pb(NO3)2 + 2 NH4OHPb(OH)2 + 2NH4NO3
On adding excess of NH4OH, chalky white ppt. of Pb(OH)2 is insoluble.
ZnSO4 + 2NH4OHZn(OH)2 + (NH4)2SO4
With excess of NH4OH, white gelatinous ppt. of Zn (OH)2 is soluble.
(iii) CuSO4 + 2NH4OHCu(OH)2 + (NH4)2SO4
With excess of NH4OH, pale blue ppt. of Cu (OH)2 is soluble.
FeSO4 + 2NH4OHFe(OH)2 + (NH4)2SO4
With excess of NH4OH, dirty green ppt. of Fe (OH)2 is insoluble.
(iv) FeSO4 + 2NH4OHFe(OH)2 + (NH4)2SO4
With excess of NH4OH, dirty green ppt. of Fe (OH)2 is insoluble.
FeCl3 + 3NH4OHFe(OH)3 + 3NH4Cl
With excess of NH4OH, reddish brown ppt of Fe (OH)3 is insoluble.