Question

Give two example for each of the following reaction in which -

1 precipitate is formed
2 heat is liberated
3 colour is changed​

Answer 1

Answer:

1 If silver nitrate solution is poured into a solution of sodium chloride, a chemical reaction occurs forming a white precipitate of silver chloride. When potassium iodide solution reacts with lead(II) nitrate solution, a yellow precipitate of lead(II) iodide is formed.

2 when coal is burnt in oxygen, carbondioxide is produced and heat is liberated. 2) slaked lime is prepared by adding water to quick lime. in this reaction also heat is give out

3 Copper reacts with oxygen, H2O and CO2 to give copper carbonate, which changes color from brown to blue or blue green. Rusting, blackening of surfaces of cut vegetables and fruits are other examples of change of color in a chemical reaction.

hope it helps you

purple you

Answer 2

Answer:

$\bold{\underline{\underline{1.Double\:displacement\:Reaction→}}}$

${\boxed{\boxed{\sf{\purple{\dag{Precipitate\:is\:formed\dag→}}}}}}$

1. $\implies$ Potassium Iodide+Lead Nitrate—Lead Iodide+Potassium Nitrate.

$\implies$ $KI+Pb(NO3)^2—PbI2+KNO3.$

☞Here a yellow coloured precipitate is formed–Lead Iodide(PbI2).

2.$\implies$ Sodium Chloride+Silver Nitrate—Silver Chloride+Sodium Nitrate

$\implies$ NaCl+AgNO3—AgCl+NaNO3

☞ Here a white coloured precipitate is formed–Silver Chloride(AgCl).

$\bold{\underline{\underline{Exothermic\:Reaction→}}}$

${\boxed{\boxed{\sf{\pink{\dag{Heat\:is\:liberated\dag→}}}}}}$

1. $\implies$ Quick lime+Water—Slaked lime+Heat

$\implies$ $CaO+H2O—Ca(OH)^2+Heat$

2. $\implies$ Magnesium+Oxygen—Magnesium Oxide+Heat

$\implies$ 2Mg+O2—2MgO+Heat.

$\bold{\underline{\underline{Displacement\:Reaction→}}}$

${\boxed{\boxed{\sf{\color{steelblue}{\dag{Colour\:is\:changed\dag→}}}}}}$

1. $\implies$ Copper Sulphate+Ferrous—Ferrous Sulphate+Copper

$\implies$ CuSO4+Fe—FeSO4+Cu

☞Here blue vitriol is converted to green vitriol.

Colour changes from $\sf{\underline{\blue{Blue}}}$$→$$\sf{\underline{\green{Green.}}}$

2. $\implies$ Copper+Oxygen+Carbon Dioxide+Hydrogen—Basic Copper Carbonate.

$\implies$ 2Cu+CO2+O2+H2O—$CuCO3.Cu(OH)^2$

☞ Here corrosion of Copper takes place, hence Copper gets converted into Basic Copper Carbonate.

Colour changes from $\sf{\underline{\color{brown}{Brown}}}$$→$$\sf{\underline{\color{green}{Green}}}$

HOPE IT HELPS.