Balbharati Class 8 General Science Solutions Chemical Change and Chemical Bond

Welcome to NCTB Solutions. Here with this post we are going to help 8th class students for the Solutions of Balbharati Class 8 General Science Book Chapter 13, Chemical Change and Chemical Bond. Here students can easily find step by step solutions of all the questions in Chemical Change and Chemical Bond. Also our Expert Science Teacher’s solved all the problems with easily understandable language with proper guidance so that all the students can understand easily. Here in this post students will get chapter 13 solutions. Here all the Question Answer are based on Balbharati latest syllabus. Here all the question and answer are based on Maharashtra State Board latest syllabus.

Chemical Change and Chemical Bond Exercise question Solutions :

Question no – (1)

Answer :

(a) An coloured arrow is drawn in between the reactants and products while writing the equation for a chemical reaction.

(b) Rusting of iron is a slow chemical change.

(c) The spoiling of food is a chemical change which is recognized from the generation of certain Physical product due to it.

(d) A colourless solution of calcium hydroxide in a test tube turns Milky on blowing in it through a blow tube for some time

(e) The white particles of baking soda disappear when put in lemon juice. this means that it is a Chemical change.

(f) Oxygen is a Reactants in respiration.

(g) Sodium chloride is Ionic compound while hydrogen chloride is Covalent compound.

(h) Electron Duplet is complete in each hydrogen in a hydrogen molecule

(i) Give two example of Element with valency 2 Chlorine (Cl₂) molecule is formed by Sharing of electrons between two chlorine atoms.

Question no – (2)

Answer :

(a) Respiration is a chemical change because we can clearly see that the reaction between these two reactants are producing two new different products.

Glucose + Oxygen → Carbon Dioxide + Water

(b) Water gets softened by adding washing soda because the reaction between dissolved salts and washing soda produces precipitates in the form of insoluble salts which are removed from water to get soft water.

Calcium chloride + Sodium carbonate → Calcium carbonate + Sodium Chloride

(c) Limestone powder disappears on adding to dilute hydrochloric acids because when it reacts with acid the first product Calcium chloride is formed which get washed away by water, the second product carbon dioxide mixes with the air and the third product water mixes with the water.

Calcium carbonate + Hydrochloric acid → Calcium chloride + Carbon dioxide + water.

(d) Bubbles are seen when lemon juice is added to baking soda because the reaction between the two produces Carbon Dioxide which creates bubbles in the reaction.

Citric acid + Sodium bicarbonate → Carbon dioxide + Sodium citrate

Question no – (3)

Answer :

(a) Photosynthesis → (iii) chemical change

(b) Water → (iv) covalent bond

(c) Sodium chloride → (v) ionic bond

(d) Dissolution of salt in water → (vi) physical change

(e) Carbon → (ii) reactant in combustion process

(f) Fluorine → (vii) tendency to form anion

(g) Magnesium → (i) tendency to lose electron.

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