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प्रश्न
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.
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उत्तर
(a) Substance P is calcium carbonate. Its common name is limestone and its chemical formula is CaCO3.
(b) Substance Q is calcium oxide (CaO).
(c) Gas R is carbon dioxide gas (CO2).
(d) Substance S is calcium hydroxide [Ca(OH)2]. Its clear solution is known as lime water.
(e) Substance T is calcium carbonate (CaCO3). Two natural forms of calcium carbonate are calcite and mollusc shell.
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संबंधित प्रश्न
Write one equation for decomposition reactions where energy is supplied in the form of heat.
Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity
State an important use of decomposition reactions.
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 silver bromide is exposed to sunlight?
Two metals X and Y form the salts XSO4 and Y2SO4, respectively. The solution of salt XSO4 is blue in colour whereas that of Y2SO4 is colourless. When barium chloride solution is added to XSO4 solution, then a white precipitate Z is formed alongwith a salt which turns the solution green. And when barium chloride solution is added to Y2SO4 solution, then the same white precipitate Z is formed alongwith colourless common salt solution.
(a) What could the metals X and Y be?
(b) Write the name and formula of salt XSO4.
(c) Write the name and formula of salt Y2SO4.
(d) What is the name and formula of white precipitate Z?
(e) Write the name and formula of the salt which turns the solution green in the first case.
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{Zn_{(s)} + H2SO4 -> ZnSO4_{(s)} + H2_{(g)}}\]
Explain the following type of chemical reaction, giving two examples for it:
Decomposition reaction
What are thermal decomposition reactions ? Explain with an example.
Give a scientific reason.
When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky.
(a) Design an activity to demonstrate the decomposition reaction of lead nitrate.
(b) Draw labelled diagram of the experimental set-up. List two main observations.
(c) Write balanced chemical equation for the reaction stating the physical state of the reactant and the products.
Classify the following reaction into different type:
\[\ce{2KClO3(s)->[\Delta] 2KCl(aq) + 3O2(g)}\]
Differentiate between direct combination reaction and a decomposition reaction.
What is electrolysis?
Electrolysis is type of ______ reaction.
Which of the following is an endothermic process?
When SO2 gas is passed through a saturated solution of H2S, which of the following reaction occurs?
These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Silver bromide decomposition is used in black and white photography.
Reason: Light provides energy for this exothermic reaction.
