Tag: chemistry

Questions Related to chemistry

Seawater can be separated in order to obtain pure substances like salt and water.

chemistry separation of substances classification of mixtures mixtures: examples and properties types of solutions

  1. True

  2. False

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Correct Option: A
Explanation:

It is possible to separate seawater to obtain pure substances like salt and waters. For this various physical and chemical processes are used.

Crude oil can be separated into petrol, diesel, kerosene, wax, etc.

chemistry separation of substances classification of mixtures mixtures: examples and properties types of solutions

  1. True

  2. False

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Correct Option: A
Explanation:

The crude oil can be separated into various substances like petrol, diesel, kerosene, wax, etc. These are very useful in supplying energy and in various processes. 

Slaked lime reacts with chlorine to give:

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. $CaCl _2$

  2. $CaO$

  3. $Ca(OCl) _2$

  4. $CaCO _3$

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Correct Option: C
Explanation:

Slaked lime reacts with chlorine to give bleaching powder.


$Ca(OH) _2  + Cl _2 \rightarrow CaOCl _2 + H _2O$

The solution of bleaching powder in water is always a clear solution.

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. True

  2. False

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Correct Option: A
Explanation:

Bleaching powder is known as calcium hypochlorite. It is marketed as bleach powder. It is white solid although commercial samples appear yellow. It is not highly soluble in water and is used in soft to medium hard water. It has two forms dry and hydrated.

The molecular formula of Baking soda is:

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. $NaHCO _3$

  2. $NaHCO _3.6H _2O$

  3. $Na _2CO _3$

  4. $Na _2CO _3.10H _2O$

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Correct Option: A
Explanation:

Baking soda is commonly known as sodium bicarbonate $ NaHC{ O } _{ 3 } $ used for cooking purposes.

Bleaching powder is effective with cold water, but ineffective with hot water. This is because of:

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. oxidation of chloride radical

  2. reduction of chloride radical

  3. reduction of hypochlorite radical

  4. hydrolysis of hypochlorite radical

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Correct Option: C
Explanation:

Bleaching action takes place due to the hypochlorite radical [$ClO^{-}$].

But when used in hot water, hot water favours reduction of the hypochlorite radical as a result of which bleaching powder is ineffective with hot water.
Generally, Bleaching powder is used as a disinfectant widely.

The reaction of $NaCl$ and $CaCO _3$ gives sodium carbonate. But this reaction cannot be used for the manufacture of washing soda since it is a reversible reaction.

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. True

  2. False

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Correct Option: A
Explanation:

The reaction of $NaCl$ and $CaCO _3$ gives sodium carbonate. But this reaction cannot be used for the manufacture of washing soda since it is a reversible reaction.

$2NaCl+CaCO _3\rightleftharpoons Na _2CO _3+CaCl _2$.

Hence the given statement is True.

Bleaching powder is soluble in cold water giving a milky solution due to:

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. available chlorine

  2. lime present in it

  3. calcium carbonate formation

  4. the absorption of carbon dioxide from atmosphere

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Correct Option: B
Explanation:

Bleaching powder on reaction with cold water form milky solution of calcium hydroxide. 

$CaOCl _2+H _2O\rightarrow Ca(OH) _2+Cl _2$

Thus because of the lime present in it, it gives a milky solution when dissolved in water.

Bleaching powder is obtained by the interaction of $Cl _2$ with a:

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. dilute solution of $Ca(OH) _2$

  2. concentrated solution of $Ca(OH) _2$

  3. dry $CaO$

  4. dry slaked lime

Show answer
Correct Option: D
Explanation:

$Ca(OH) _2 +Cl _2 \rightarrow Ca(OCl)Cl + H _2O$
Bleaching powder is obtained by the interaction of $Cl _2$ with a dry slaked lime.

Cobalt chloride acts as a calalyst, in the decomposition of bleaching powder.

chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

$CoCl _2$ is used as catalyst in the decomposition of bleaching powder.