CBSE Class 10 Science Chapter-2 Acids, Bases and Salts Important Questions – Free PDF Download
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CBSE Class 10 Science Acids, Bases and Salts Chapter-2 Important Questions
CBSE Class 10 science Important Questions Chapter 2 – Acids, Bases and Salts
5 Mark Questions
1. (a) The PH of rain water collected from two cities A and B was found to be 6 and 5 respectively. Water of which city is more acidic? Find out the ratio of hydrogen ion concentration in the two samples of rain water?
(b) Arrange the following in order (ascending) of their P4 values.
solution, Blood, lemon Juice.
Ans. (a) 
For city A 
For city B
(b) Increasing order of PH values
Lemon juice < Blood < NaOH solution.
2. (a) Why does an aqueous solution of acid conduct electricity?
(b) How does the concentration of hydrogen ions 
changes when the solution of an acid is diluted with water?
(c) Which has higher pH. A concentrated or dilute solution of HCL?
(d) What would you observe on adding dil HCL acid to
(i) Sodium bicarbonate placed in a test tube.
(ii) Zinc metal in a test tube.
Ans. (a) An aqueous solution of an acid conducts electricity because in water an acid (HCl) dissociates to give ions. Since the current is carried out by the movement of ions, an aqueous solution of acid conducts electricity.
(b) During dilution, more of acid dissociates into ions. Thus concentration of 
ions will increase on dilution.
(c) Even on increasing ions, the number of ions per unit volume decreases. Therefore, ph will increases on dilution.
(d) (i) CO2 gas will evolves accompanied by brick effervescence.
NaHCO3 (s) + HCl (aq) 
NaCl (aq) + CO2 (g) + H2O (aq)
(ii) H2 gas will evolves accompanied by brick effervescence
Zn (s) + 2HCl (aq) ZnCl (aq) + H2O (g)
3. A road tanker carrying an acid was involved in an accident and its contents spilled on the road. At the side of the road iron drain cover began melting and fizzing as the acid ran over them. A specialist was called to see if the acid actually leaked into the nearby river.
(a) Explain why specialist could carry out sample test to see of the river water contains some acid or not
(b) Suggest a better report name for the word ‘melting’
(c) Explain why the drain covers began fizzing as the acid ran over them.
Ans. (a) It can be done by adding a strip of blue litmus paper into a tube containing a small amount of sample water if the colour changes into red, this means that some acid has gone into the river.
(b) The acid has reacted chemically with the drain cover which is usually made of iron. The correct word is corrosion.
(c) Iron reacts with an acid 
to evolve 
gas. Since the gas is released immediately accompanied by large number of bubbles Fizzing of detain covers is expected.
4. Write word equations and then balanced equations for the reaction taking place when:
(a) Dilute Sulphuric acid reacts with zinc granules.
(b) Dilute hydrochloric acid reacts with magnesium ribbon.
(c) Dilute Sulphuric acid reacts with aluminum powder
(d) Dilute hydrochloric acid reacts with iron fillings.
Ans. (a) Zinc + Sulphuric acid Zinc sulphate +Hydrogen
Zn + H2SO4 ZnSO4 + H2
(b) Magnesium + Sulphuric acid magnesium chloride +Hydrogen gas
Mg + HCl MgCl2 +H2
(c) Aluminum + Sulphuric acid Aluminum sulphate +Hydrogen gas
Al + H2S04 Al2 (S04)3+ H2
(d) Iron + Hydrochloric acid Iron chloride +Hydrogen
Fe + 2HCl FeCl2 + H2
5. Compound such as alcohols and glucose also contain hydrogen but are not categorized as acids. Describe an activity
Ans. Alcohol and glucose both contain hydrogen but not categorized as acids. This can be proved by following activity.
Material required: – Beaker, nails, battery, connecting wires, bulb, switch and alcohols.
Procedure:
1. Set up the experiment as follows
2. Take ethyl alcohol in the beaker in the beaker.
3. When the switch is turned on, the bulb does not glow.
4. Take glucose solution in place of alcohols but bulb does not glow.
6. A compound X is bitter in taste. It is a component of washing powder& reacts with dil. HCI to produce brisk effervescence dur to colourless, odourless gas Y wich turns lime water milky due to formation of Z. When excs of 
is passed, ilkiness disappears due to formation of P. Identify X, Y, And Z & P.
Ans.
7. When gas pass through saturated solution of ammonia cal brine, two compound ‘X’ and ‘Y’ are form. ‘Y’ is used as antacid and decomposes to form another solid ‘Z’. Identify ‘X’, ‘Y’, ‘Z’ and write chemical equations.
Ans.
8. A substance ‘X’ used in the kitchen for making tasty crispy pakoras and is also an Ingredient of antacid. Name the substance ‘X’.
(i) How does ‘X’ help to make cakes and bread soft and spongy.
(ii) Is the pH value of solution of ‘X’ is lesser than or greater than 7.0?
Ans.
(i) When gas escapes as bubbles it leaves behind pores which make the cake or bread soft and spongy.
(ii) It is a salt of strong base so the pH of the solution will be more than 7.0
