explain activity 2.9 acid base and salt...class 10th

Dear Student
​​​
Activity 2.9 asks us to react solid sodium chloride with concentrated sulphuric acid and check if the gas evolved turn the blue litmus paper into red or not.
Observation: Gas fumes produce, but do not turn the blue litmus paper into the red.
Explanation: Solid sodium chloride reacts with concentrated sulphuric acid and forms dry hydrochloric acid gas.
Here HCl is produced in gaseous form as there is no water.
NaCl(s) + H2SO4(conc.) —> Na2SO(s)+ HCl(g)
A litmus paper works on H+ or OH- ion. Since there is no water in HCl gas, HCl does not dissociate into its ion and does not turn the blue litmus red.
HCl (aq) ——-> H+ + Cl
Inference/Conclusion: Concentrated acids and bases need an aqueous medium to turn litmus paper.

Regards

  • 0
What are you looking for?