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प्रश्न
Give a scientific reason.
When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky.
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उत्तर
- When limestone is heated, calcium oxide and carbon dioxide gas are formed.
\[\ce{\underset{\text{carbonate}}{\underset{\text{Calcium}}{CaCO_{3(s)}}} + Heat -> \underset{\text{oxide}}{\underset{\text{Calcium}}{CaO_{(s)}}} + \underset{\text{dioxide}}{\underset{\text{Carbon}}{CO2\uparrow}}}\] - When carbon dioxide gas is passed through freshly prepared lime water, the solution turns milky due to the formation of calcium carbonate, which is insoluble in water.
\[\ce{\underset{\text{hydroxide}}{\underset{\text{Calcium}}{Ca(OH)2_{(aq)}}} + \underset{\text{dioxide}}{\underset{\text{Carbon}}{CO_{2(g)}}} -> \underset{\text{carbonate}}{\underset{\text{Calcium}}{CaCO_{3(s)}}} + \underset{\text{Water}}{H2O_{(l)}}}\]
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संबंधित प्रश्न
Write the balanced chemical equation for the following and identify the type of reaction.
\[\ce{Zinc carbonate(s) -> Zinc oxide(s) + Carbon dioxide(g)}\]
Write one equation for decomposition reactions where energy is supplied in the form of heat.
Rewrite the following statements by selecting the correct options:
\[\ce{CaCO3 ->[\Delta] CaO + CO2 ^}\] is a __________ reaction.
A solid substance P which is very hard is used in the construction of many buildings, especially flooring. When substance P is heated strongly, it decomposes to form another solid Q and a gas R is given out. Solid Q reacts with water with the release of a lot of heat to form a substance S. When gas R is passed into a clear solution of substance S, then a white precipitate of substance T is formed. The substance T has the same chemical composition as starting substance P.
(a) What is substance P? Write its common name as well as chemical formula.
(b) What is substance Q?
(c) What is gas R?
(d) What is substance S? What is its clear solution known as?
(e) What is substance T? Name any two natural forms in which substance T occurs in nature.
What type of reaction is represented by the digestion of food in our body?
Give one example of a decomposition reaction which is carried out by applying heat.
Give one example of a decomposition reaction which is carried out with electricity.
What type of chemical reaction is used to extract metals from their naturally occurring compounds like oxides or chlorides?
What type of chemical reaction take place when electricity is passed through water?
What is the colour of ferrous sulphate crystals? How does this colour change after heating?
What is a decomposition reaction?
Which of the following can be decomposed by the action of light?
(a) NaCl
(b) KCl
(c) AgCl
(d) CuCl
A metal salt MX when exposed to light splits up to form metal M and a gas X2. Metal M is used in making ornaments whereas gas X2 is used in making bleaching powder. The salt MX is itself used in black and white photography.
(a) What do you think metal M is?
(b) What could be gas X2?
(c) Name the metal salt MX.
(d) Name any two salt solutions which on mixing together can produce a precipitate of salt MX.
(e) What type of chemical reaction takes place when salt MX is exposed to light? Write the equation of the reaction?
Explain the following type of chemical reaction, giving two examples for it:
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MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Thermal decomposition of a substance is brought about with the help of
- reactants
- water
- wind
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What do you mean by redox reaction ? Explain with the help of an example.
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\[\ce{2KClO3(s)->[\Delta] 2KCl(aq) + 3O2(g)}\]
Classify the following reaction into –
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- Displacement
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Give a balanced equation for –
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Complete the statement by filling in the blank with the correct word:
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Electrolytic decomposition and photochemical decomposition.
The chemical reaction in which two or more products are formed from a single reactant is called ______ reaction.
What is electrolysis?
Electrolysis is type of ______ reaction.
Chemical volcano is an example of ______ type of reaction.
Which of the following is an endothermic process?
Balance the following chemical equation and identify the type of chemical reaction.
`"HgO"("s") overset("(heat)")(->) "Hg"("l") + "O"_2("g")`
The reaction of calcium carbonate, with freshly prepared lime water, is shown below:
Answer the questions with the help of a diagram:
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- What change in colour is observed in lime?
- Write the chemical equation.
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Assertion: Silver bromide decomposition is used in black and white photography.
Reason: Light provides energy for this exothermic reaction.
Complete the following reaction:
\[\ce{C_12H_22O11->[Heat]}\] ______ + ______.
