Question

5. Write the chemical reaction where the following changes
are observed.
(a) Gas is evolved (b) Colour change is noticed
(c) Precipitate is formed (d) Physical state is changed​

Answer 1

Answer:

cu + h2so4----cuso4 +h2<a>

Answer 2

Answer:

Explanation:

The equations will be -

Colour change is noticed -

Cu (s) + 2AgNO3 (aq) →→→ Cu(NO3)2(aq) + 2Ag

With the above reaction, the solution will turn into blue colour and a shiny silver metal will be deposited.

Change in temperature -

NaOH + HCl →→→ NaCl +  H2O+ heat

With the above reaction, the temperature will increase because heat will be evolved.

Physical state is changed -

CaCO3(s)+Heat →→→ Hao(s)+CO2(g)

The chemical reaction between quicklime and water is characterised by change in temperature, thus evolving carbon di oxide.

Precipitate is formed -

Pb(NO3)2 (aq) + 2KI (aq) →→→ Pbl2 (s) + 2KNO3 (aq)

In the above reaction, a yellow precipitate of Pbl2will be formed.