Chemistry, asked by Nameera786, 1 year ago

The favourable condition for melting of ice is ----- 1) low pressure 2) high pressure 3) low temperature 4) absence of catalyst
I known the answer is high pressure...but i can't understand why??
Can someone plz explain this....

Answers

Answered by shrivastavavina
61
Hii
A) Effect of temperature on solubility: Some solids absorb heat while some evolve heat on dissolution. Hence according to this principle solubility of the former class of solids increases with rise of temperature.

For example:

(i) KNO_3 + aq. \leftrightharpoons KNO_3 (aq.) - Q \hspace{3mm}kcal \hspace{3mm}mol^{-1} (\text{Endother} . )

(ii) Ca(OH)_2 + aq. \leftrightharpoons Ca(OH)_2 (aq.) + Q \hspace{3mm}kcal \hspace{3mm}mol^{-1} (\text{Exother}.)

With rise of temperature solubility of KNO_3 increases while that of Ca(OH)_2 decreases.



(B) Effect of pressure on solubility: Since on dissolution of gas volume decreases, hence on increasing pressure, solubility of gas increases. On the other hand, if volume of the solution increases on dissolution of solid then solubility of the solid decreases with rise of pressure.

On operating carbonated water (soft drinks) CO_2 comes out, due to decrease of pressure, it’s solubility decreases.



(C) Effect of temperature and pressure on melting of ice: Since ice melts with absorption of heat and decreases in volume, hence both temperature and pressure effect the melting of ice. Since the change of ice into water is an endothermic process hence with rise of temperature ice melts into water. Since volume of ice is more than that of water so increase of pressure favour melting.

\text{Ice} \leftrightharpoons \text{Water}- Q kcal \hspace{3mm} mol^{-1}


(D) Effect of temperature and pressure on vapourization of water: When water changes into vapour heat is absorbed hence rise of temperature is favourable but in this process volume of vapour increases hence rise of pressure is not favourable for forward reaction.

\text{Water} \leftrightharpoons \text{Vapours}- Q kcal \hspace{3mm} mol^{-1}
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shrivastavavina: Please also thank it
zoya901: kk
Answered by zoya901
28
it is because of high pressue as the substances present in the ice gets heated up and these molicules gets separated as when they r in the solid form hese substances r close and when we heat it the water oxygen gets seprate
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