Q2 of 11 Page 94

Explain by writing a word equation.

Bubbles are seen on adding lemon juice to baking soda.

Baking soda is chemically sodium bicarbonate which is a base. Lemon juice is an acidic substance and hence the addition of lemon juice to basic baking soda results in the neutralization reaction. Lemon juice is chemically composed of citric acid. During this chemical change, carbon dioxide is evolved. This carbon dioxide is seen as bubbles. The reaction can be expressed in word equation as :
Sodium bicarbonate + citric acid Carbon dioxide + Water + Sodium citrate


More from this chapter

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2

Explain by writing a word equation.

Hard water gets softened on mixing with a solution of washing soda.

 2

Explain by writing a word equation.

Lime stone powder disappears on adding to dilute hydrochloric acids.

 3

Match the pairs.

Column A


a. Photosynthesis


b. Water


c. Sodium chloride


d. Dissolution of salt in water


e. Carbon


f. Fluorine


g. Magnesium


Column B


i. Tendency to lose electrons


ii. Reactant in combustion process


iii. Chemical change


iv. Covalent bond


v. Ionic bond


vi. Physical change


vii. Tendency to form anion

 4

Show with the help of diagram of electronic configuration how the following compound are formed from the constituent atoms.

Sodium chloride