Tag: chemical from common salt

Questions Related to chemical from common salt

Oxidation number of $Cl$ in ${ CaOCl } _{ 2 }$ (bleaching powder) is:

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

  1. zero, since it contains ${ Cl } _{ 2 }$

  2. $-1$, since it contains ${ Cl }^{ - }$

  3. $-1$, since it contains ${ ClO }^{ - }$

  4. $+1$ and $-1$ since it contains ${ ClO }^{ - }$ and ${ Cl }^{ - }$

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Correct Option: D
Explanation:
In bleaching powder,$CaOCl _2,$ the two $Cl$ atoms are in different oxidation states i.e.,one $Cl$ atom having oxidation number of $-1$ and the other as $OCl^-$ having oxidation number of $+1$.
Therefore,$+1$ and $-1$ Since it contains $ClO^-$ and $Cl^-$
Ans is option $D$

Bleaching powder is obtained by treating chlorine with ________ .

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

  1. $CaO$

  2. $CaC{O _3}$

  3. $CaS{O _4}$

  4. $Ca{(OH) _2}$

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Correct Option: D

Bleaching powder is disinfectant for purification of water when water born germs are killed. But disinfectant activity is destroyed. It is due to its disproportionation into:

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

  1. $ CaCl _2$  and $Cl _2 $

  2. $ CaCl _2$  and $Ca(ClO _3) _2 $

  3. $ CaO$  and $Cl _2 $

  4. $ CaO, Cl _2$ and $CaCl _2 $

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Correct Option: B
Explanation:
Bleaching powder is disinfectant for purification of water when water born germs are killed. But disinfectant activity is destroyed because of the degradation of high grade of bleaching powder.
These include disproportionation to give $Ca(ClO _3) _2$ and $CaCl _2$, and with the evolution of $Cl _2$ or $O _2$ depending on the presence or absence of water.

Option B is the correct answer.

The active constituent of bleaching powder is:

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

  1. $ Ca(OCl) _2$

  2. $ Ca(OCl)Cl $

  3. $ Ca(ClO _2) _2 $

  4. $ Ca(ClO _2)Cl$

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Correct Option: A
Explanation:

The active constituent of bleaching powder is: $Ca(OCl) _2$

$ CH _3CH _2OH$ on reaction with bleaching powder forms:

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

  1. $ CHCl _3 $

  2. $ CClCHO$

  3. $ CH _2ClCHO$

  4. $ CCl _4 $

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Correct Option: A
Explanation:
When bleaching powder is distilled with alcohol, chloroform is produced.

$CH _3CH _2OH +CaOCl _2 \rightarrow CHCl _3 +Ca(HCOO) _2$

Hence, option A is correct.

Slaked lime and chlorine reacts to produce :

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

  1. quick lime

  2. $CaCl _2$

  3. $CaOCl _2$

  4. mixture of $CaCl _2$ and $Ca(OCl _2)$

Show answer
Correct Option: D
Explanation:

$Ca(OH) _2+\underset{\text{dry}}{Cl _2}\xrightarrow{below\,35^oC} \underset{\text{Bleaching powder}}{CaOCl _2 + H _2O}$


$2Ca(OH) _2 + 2Cl _2\xrightarrow{red\, heat} 2CaCl _2 + 2H _2O + O _2\uparrow$

The amount of chlorine obtained from a sample of bleaching powder by treatment with excess of dilute acid or $ \displaystyle CO _{2}$ is called available chlorine.

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: B
Explanation:

The available chlorine is defined as the percentage of chlorine made available by bleaching powder when treated with dilute acids. The available chlorine present in bleaching powder sample is determined iodometricaliy by treating its solution with an excess of potassium iodide solution in the acidic medium.

Bleaching powder is used :

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

  1. for bleaching cotton, wood pulp

  2. as a disinfectant and germicide

  3. for the manufacture of chloroform

  4. as a reducing agent in industries

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Correct Option: A,B,C
Explanation:

Bleaching powder + ethanol $\rightarrow$ chloroform
Bleaching powder is used for bleaching cotton, wood pulp, it is also used as a disinfectant and germicide.

Bleaching powder has a strong bleaching action due to:

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

  1. calcium

  2. chlorine molecule

  3. nascent oxygen

  4. chloride ion

Show answer
Correct Option: C
Explanation:

The bleaching powder has a strong bleaching action due to the formation of nascent oxygen.

When bleaching powder reacts with a small amount of acid, it gives nascent oxygen. 
Thus, it acts as an oxidizing agent and thus acts as a bleaching agent.

$2CaOCl _2 +H _2SO _4 \rightarrow CaCl _2+CaSO _4+2HOCl$

$2HOCl \rightarrow 2HCl+2[O]$

Materials used in the manufacture of bleaching powder are :

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

  1. lime stone and chlorine

  2. quick lime and chlorine

  3. slaked lime and HCl

  4. slaked lime and chlorine

Show answer
Correct Option: D
Explanation:

Bleaching powder is calcium oxychloride which is formed by reacting calcium hydroxide with chlorine.