3. Distilled water does not conduct electricity. Why? (AS1)
4. Dry hydrogen chloride gas does not turn blue litmus to red whereas aqueous hydrogen chloric
acid does.Why? (AS1)
5. Draw a neat diagram for showing acid solution in water conducting electricity. (AS5)
6. Why the flow of acid rain into a river make the survival of aquatic life in a river difficult? (AS7)
7. What is baking powder? How does it make the cake soft and spongy? (AS7)
8. Give two important uses for each of washing soda and baking soda. (AS7)
1. Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11,
7 and 9, respectively, classify the solutions as given below.(AS1)
(a) neutral (b) strongly alkaline (c) strongly acidic (d) weakly acidic (e) weakly alkaline
2. Why does tooth decay start when the pH of mouth is lower than 5.5? (AS1)
3. A milkman adds a very small amount of baking soda to fresh milk. (AS2)
a) Why does he shift the pH of the fresh milk from acidic nature to slightly alkaline?
b) Why does this milk take a long time to set as curd?
4. Plaster of Paris should be stored in moisture – proof container. Explain why? (AS1)
5. Magnesium ribbons of same size are taken in test tubes A and B. Hydrochloric acid is
added to test tube A, while acetic acid is added to test tube B. The concentrations of both
the acids is same. In which test tube will the fizzing occur more vigorously ? why? (AS3)
1. Fresh milk has a pH of 6.6. Explain why the pH changes as it turns into curd? (AS3)
2. How do you prepare an indicator using beetroot? Explain. (AS5)
1.The colour of methyl orange indicator in acidic medium is[ ]
A) Yellow B) green C) orange D) red
2. The colour of phenolphthalein indicator in basic solution is [ ]
A) yellow B) green C) pink D) orange
3. Colour of methyl orange in alkali conditions? [ ]
A) orange B) yellow C) red D) blue