Tag: chemistry

Questions Related to chemistry

$ 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 $

Show answer
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

Show answer
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

Show answer
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.

Which of the following has the strongest bleaching property?

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

  1. Chlorine

  2. Fluorine

  3. Bromine

  4. Iodine

Show answer
Correct Option: A
Explanation:

Chlorine is strongest bleaching property.

Chlorine is a very strong oxidizing agent, which is used commercially as a bleaching agent and as a disinfectant, It is strong enough to oxidize the dyes that give wood pulp its yellow or brown color, for example, thereby bleaching out this color, and strong enough to destroy bacteria and thereby acts as a germicide. 

Which one of the following is a correct statement?

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

  1. Bleaching powder is a compound

  2. Bleaching powder is mixture of calcium chloride and calcium hypochloride

  3. Bleaching powder is a mixture of calcium chloride,calcium hypochlorite and slaked lime

  4. Bleaching powder is a mixture of sodium chloride and sodium hypochloride

Show answer
Correct Option: A
Explanation:
Calcium hypochlorite is an inorganic compound with formula $Ca(ClO) _2$. As a mixture with lime and calcium chloride, it is marketed as chlorine powder or bleach powder for water treatment and as a bleaching agent.

The real bleaching agent present in bleaching powder is:

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

  1. chlorine

  2. oxygen

  3. CaO

  4. None of the above

Show answer
Correct Option: A
Explanation:

Calcium oxychloride (CaOCl2) is known as bleaching powder. In the presence of small amount of dilute acid, it gives nascent oxygen which acts as an oxidising and bleaching agent. When it is treated with excess of dilute acids, chlorine is evolved which is responsible for the bleaching action of bleaching power.

Bleaching powder is:

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

  1. $CaO _2Cl$

  2. $CaOCl _2$

  3. $CaClO _2$

  4. $CaCl _2+O _2$

Show answer
Correct Option: B
Explanation:

The correct formula for Bleaching powder is CaOCl2. One chlorine is directly bonded to calcium while other to the oxygen atom.