You are provided with 90 ml of distilled water and 10 ml of concentrated sulphuric acid to prepare dilute sulphuric acid. (i) what is the correct way of preparing dilute sulphuric acid? Give reason. (ii) how will the concentration of h3o + ions change on dilution?
Answers
Answer:
1)The 10ml concentrated H2SO4(Sulphuric acid) should be added drop wise to 90ml of water not the other way around.
2) The conc. of H30+ ions decreases on dilution
Explanation:
1) The H2SO4 reacts aggressively with H2O and is highly exothermic. If one drop of water falls into the acid solution then the solution will splash and can burn your skin. Therefore, acid should be added to water in a drop wise manner.
2) The H30+ ions are just H+ ions. The Concentration = Mole/Volume. Here the no. of mole of H+ doesn't the change rather you have added water and the Volume has increased. Therefore conc. of H30+/H+ ions decrease.
Answer:
(i) Add 10 mL of concentrated sulphuric acid slowly to 90 mL of water with constant stirring. Dilution of acid is a highly exothermic process. If water is added to concentrated sulphuric acid, heat generated causes the mixture to splash leading to burns and the glass container can break.
(ii) Decreases per unit volume.