(a)while diluting an acid, why is it recommended that the acid should be added to water and not water to the acid? (b) Dry hydrogen chloride gas does not change the colour of dry litmus paper. Why?
Answers
your a part answer is shown in first picture and your B part answer is shown in second picture I hope you understand all the concepts really science is very interesting be happy and thank you for your questioning
Answer: ( a ) Dilution of concentrated acid is highly exothermic. The heat produced is so large that the solution may splash out or the glass beaker may break due to excessive localised heat. To slow down the exothermic reaction, concentrated acid is added into water slowly with stirring.
( b ) HCl gas does not dissociate to give H+ ions and hence does not change the colour of dry litmus paper. Moist litmus paper contains H2O. In presence of H2O, HCl gas dissolves to form HCl ( aq ) which dissociates to give H+ ions.
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