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The pH plays an important role in our daily life. Strength of acids and bases depends on the number of $\ce{H+}$ ions and $\ce{OH-}$ ions produced by these respectively. pH scale helps in predicting the strength of acids and bases by measuring hydrogen ion concentration in a solution.
Answer the following :
(a) What type of indicator is used to predict how strong an acid or base is ?
(b) Three solutions A, B and C showed pH as 3, 5 and 7. Which solution has the highest concentration of $\ce{H+}$ ions ?
(c) What are strong acids and weak acids ?
OR
(c) (i) Under what condition is rainwater called acid rain ?
(ii) In the following acids, identify weak acids :
Nitric acid, hydrochloric acid, acetic acid, sulphuric acid, formic acid.
Answer the following :
(a) What type of indicator is used to predict how strong an acid or base is ?
(b) Three solutions A, B and C showed pH as 3, 5 and 7. Which solution has the highest concentration of $\ce{H+}$ ions ?
(c) What are strong acids and weak acids ?
OR
(c) (i) Under what condition is rainwater called acid rain ?
(ii) In the following acids, identify weak acids :
Nitric acid, hydrochloric acid, acetic acid, sulphuric acid, formic acid.
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(a) Universal indicator (1 Mark)
(b) A/ (pH = 3) (1 Mark)
(c) • Strong acids give more $\ce{H+}$ ions in water. (1 Mark)
• Weak acids give less $\ce{H+}$ ions in water. (1 Mark)
(c) (i) When pH < 5.6 (1 Mark)
(ii) Weak acid: acetic acid, formic acid (½ + ½ = 1 Mark)
(b) A/ (pH = 3) (1 Mark)
(c) • Strong acids give more $\ce{H+}$ ions in water. (1 Mark)
• Weak acids give less $\ce{H+}$ ions in water. (1 Mark)
(c) (i) When pH < 5.6 (1 Mark)
(ii) Weak acid: acetic acid, formic acid (½ + ½ = 1 Mark)