Tag: substances in common use

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Questions Related to substances in common use

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

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

  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 ${ Cl }^{ - }$
Reveal answer Fill a bubble to check yourself
D Correct answer
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 $D$
Multiple choice chemistry substances in common use chemical from common salt compounds of carbon some useful compounds in everyday life

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:

  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 $
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Slaked lime and chlorine reacts to produce :

  1. quick lime
  2. $CaCl _2$
  3. $CaOCl _2$
  4. mixture of $CaCl _2$ and $Ca(OCl _2)$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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


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

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

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.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Bleaching powder is used :

  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
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

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

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

Bleaching powder has a strong bleaching action due to:

  1. calcium

  2. chlorine molecule

  3. nascent oxygen

  4. chloride ion
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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