CLASS 10th

“IMPORTANT QUESTION FOR CHAPTER 1 “CHEMICAL EQUATIONS”

Here are the some important question for class 10th chapter 1 Chemical Equations

Important Questions –

Ques-1 What do you mean by exothermic and endothermic reactions ? Give examples.

Ques-2 Why is respiration considered an exothermic reaction ? Explain.

Ques-3 What is a balanced chemical equation ? Why should the chemical equations be balanced.

Ques-4 Explain the following  in terms of gain of oxygen or loss of oxygen with two examples each:

  • Oxidation Reaction.
  • Reduction

Ques-5 Give reasons for the following

  • When copper turnings are added to silver nitrate solution, the solution becomes blue in the colour after some time.
  • Blue colour of copper sulphate solution fades when iron filings are added to it.

Ques-6 Oil and fat containing  food items are flushed with nitrogen. Why?

Ques-7 What are decomposition reaction ? Explain with examples.

Ques-8 What are the difference between displacement and double displacement reactions ? Write equations for these reactions.

Ques- 9 Define Oxidising agent and reducing agent in terms of electronic concept of Oxidation and Reduction.

Ques-10 What happens when a piece of

  • Zinc metal is added to copper sulphate solution ?
  • Aluminium metal is added  to diluite hydrochloric acid.
  • Silver metal is added to copper sulphate solution.

Ques- 11 On heating blue coloured powder of copper(II) nitrate in a boiling tube, copper oxide ( black) , oxygen gas and a brown gas ‘X’ is formed.

  • Write a balanced chemical equation of the reaction.
  • Identify the brown gas X evolved.
  • Identify the type of reaction.
  • What could be the PH range of aqueous solution of the gas X ?

Ques -11 On adding a drop of barium chloride solution to an aqueous solution sulphite, white precipitate is obtained.

  • Write a balanced chemical equation of the reaction involved.
  • What other name can be given to this precipitation reaction ?
  • On adding dilute hydrochloric acid to the dilute mixture, White precipitate disappears why?

Ques 12 During the reaction of some metals with dilute hydrochloric acid, following observations were made.

  • Silver metal does not show any change.
  • The temperature of the reaction mixture rises when alluminium (AL) is added.
  • The reaction of sodium metal is found to be highly explosive.
  • Some bubbles of a gas are seen when lead (PB) is reacted with the acid.

Explain these observations giving suitable reasons.

Ques 13 Which among following are physical or chemical changes?

  • Evaporation of patrol.
  • Burning of liquefied petroleum Gas (LPG).
  • Heating of an iron rod to red hot.
  • Curdling of milk.
  • Sublimation of solid ammonium chloride.

 

Ques-14  A shiny brown coloured element ‘X’ on heating in air beomes black I colour. Name the element ‘X’ and the black coloured compound formed ?

Ques-15 Write the balanced chemical equations for the following reactions:

  • Calcium hydroxide + Carbon dioxide ——–à Calcium carbonate + water
  • Zinc + Silver Nitrate à  Zinc Nitrate + Silver
  • Aluminium + Copper Chloride à   Aluminium chloride + Copper
  • Barium chloride +potassium sulphate à Barium sulphate + Potassium chloride.

Ques-15 Ethane burns in oxygen to form carbon dioxide and water. Write balanced chemical equation for the reaction.

Ques-16 Calcium reacts with nitrogen to form calcium nitride. Write balanced chemical reaction.

Ques-17 In the formation of a compound XY, atoms of element X lose two electrons each while the atoms of element Y gain two electrons each Identify.

  • The element undergoing oxidation.
  • The element undergoing reduction.
  • The element acting as oxidising agent.
  • The element acting as reducing agent.

Ques-18 Translate the following statements into chemical equations and then balance them.

  • Hydrogen gas combines with nitrogen to form ammonia.
  • Hydrogen sulphide gas burns in air to give water and Sulphur dioxide.
  • Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
  • Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Ques-19

 

Ques-20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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