An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change ?
As the solution turns red litmus solution blue, it must be basic. To reverse the change, we must add an acid.
NaOH is obtained by electrolysis of
2NaCl + 2H2O ------- > 2NaOH + H2 + Cl2
One of the constituents of baking powder is sodium hydrogencarbonate, the other constituent is
To decompose sodium hydrogencarbonate, we require an acid. Since it is used in food, we use a mild organic acid which is not toxic to human system.
Lime water reacts with chlorine to form
Ca(OH)2 + Cl2 → CaOCl2 + H2O
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue ?
Only a basic solution will change the colour of pH paper to greenish-blue.
Ag2S reacts with H2S04 to form
Ag2S + H2S04 → Ag2S04 + H2S
Which of the following statements are true for acids ?
Acids possess sour taste and turn blue litmus paper red.
pH of H20 is
pH of H20 is 7 because it is neutral.
Which of the following are present in a dilute aqueous solution of hydrochloric acid ?
Hydrochloric acid ionises as follows :
HCl→ H+ +Cl-
H+ ions combine with water molecules to form H30+. Therefore, the ions present in dilute aqueous solution of hydrochloric acid are H30+ and Cl-.
NaHC03 formed by reaction of
NaOH + H2C03→ NaHC03 + H20