Describe a conspicuous change observed when (i) a solution of NaCl is added to a sol of hydrated ferric oxide.

[Hint : Mutual precipitation/coagulation took place.]

[Hint : K3[Fe(CN)6]]

(i) A yellow precipitate of lead iodide (PbI2) is formed. (ii) Precipitation reaction/Double displacement reaction. (iii) Pb(NO3)2(aq) + 2KI(aq) ------> PbI2(s) +   2KNO3 (aq) Lead nitrate           Potassium iodide    Lead iodide     Potassium nitrate    ...

(i) The positively charged colloidal particles of Fe(OH)3 get coagulated by the oppositely charged Cl- ions provided by KCl. (ii) On passing direct current, colloidal particles move towards the oppositely charged...

(i) The positively charged colloidal particles of Fe(OH)3 get coagulated by the negatively charged ions provided by electrolyte. (ii) The path of light becomes visible due to scattering of light by...

Iron absorbed by plants is Ferric

 Pb2+ ion concentration will decrease to keep Ksp constant.

HCl in the solution provides Cl ions. This increases the ionic product in NaCl and so the solid NaCl starts separating out.

(b) Red soils are very poor in lime, humous and potash.

Na2SO4(aq) + BaCl2(aq)→BaSO4(s) + 2NaCl(aq) A white precipitate of barirrm sulphate insoluble in water is observed. It is a double displacement reaction