Acid, Bases & Salt - Grade X (11/9/2023)

1) Which fruit is basic in nature?

• a) Apples

• b) Oranges

• c) Strawberries

• d) Banana

A student listed some food items as shown.

Which option classifies the food items on the basis of acidic and basic nature of food?

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A basic solution is added to a test tube. A blue and red litmus paper is dipped into the basic

solution. What will happen to both litmus papers?

• a) blue litmus paper: changes colour; red litmus paper: changes colour

• b) blue litmus paper: changes colour; red litmus paper no colour change

• c) blue litmus paper: no colour change; red litmus paper: changes color

• d) blue litmus paper: no colour change; red litmus paper: no colour change

A solution of pH 2 is filled in two separate beakers. A few drops of methyl orange and

phenolphthalein are added into separate solutions. How will the colour of the indicators

change?

• a) methyl orange: red; phenolphthalein: pink

• b) methyl orange: orange; phenolphthalein: pink

• c) methyl orange: Red; phenolphthalein: colourless

• d) methyl orange: orange; phenolphthalein: colourless

When dilute sulphuric acid is added to a solid X, a gas Y is formed along with the formation of

the salt of the solid. What could be X and Y?

• a) X: zinc; Y: oxygen

• b) X: zinc; Y: hydrogen

• c) X: copper; Y: oxygen

• d) X: carbon; Y: hydrogen

When a base reacts with a metal, it forms a salt and hydrogen gas is released. By what method

the presence of hydrogen can be detected?

• a) by water

• b) by litmus paper

• c) by methyl orange

• d) by a burning candle

A student did an activity in which he added sodium bicarbonate to hydrochloric acid. It forms

the carbon dioxide gas. The gas released is passed through lime water. What change will be

observed in lime water

• a) bubbles are formed

• b) white precipitate is formed

• c) the solution becomes colourless

• d) the colour of solution becomes red

A metal carbonate reacts with a solution X which forms a salt, water, and a gas Y. What are X

and Y?

• a) X: hydrochloric acid; Y: hydrogen

• b) X: sodium hydroxide; Y: hydrogen

• c) X: hydrochloric acid; Y: carbon dioxide

• d) X: sodium hydroxide; Y: carbon dioxide

Which equation for the reaction between hydrochloric acid and sodium hydroxide is correct?

• a) HCl + NaOH -> NaCl + H₂O

• b) HCl + 2NaOH -> Na₂Cl + H₂O

• c) 2HCl + NaOH -> 2NaCl + H₂O

• d) 2HCl + NaOH -> NaCl + 2H₂O

A student placed 10 mL HCl and NaOH in two separate beakers.

In beaker 1, 4 mL of NaOH is added whereas in beaker 2, 4 mL of HCl is added. The student notes the possible change in pH in both solutions. Which change in pH is correct?

• a) A

• b) B

• c) C

• d) D