Tag: chemistry

Questions Related to chemistry

A mixture of $ZnCl _2$ and $PbCl _2$ can be separated by:

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. disitillation

  2. crystallisation

  3. sublimation

  4. adding acetic acid

Show answer
Correct Option: B
Explanation:

A mixture of $ZnCl _2$ and $PbCl _2$ is a non- homogeneous mixture. Hence, they can be separated using method of crystallization.

The $pK _{a}$ of oxoacids of chlorine in water follows the order:

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. $HClO < HClO _{3} < HClO _{2} < HClO _{4}$

  2. $HClO _{4} < HClO _{3} < HClO _{2} < HClO$

  3. $HClO _{4} < HClO _{2} < HClO _{3} < HClO$

  4. $HClO _{2} < HClO < HClO _{3} < HClO _{4}$

Show answer
Correct Option: B
Explanation:

The higher the oxidation number of chlorine, higher is the acidic strength of the oxoacid of chlorine. $HClO _4$ has the highest number of oxygen atoms, hence the oxidation number of chlorine is highest in it. Therefore, it is the most acidic. Therefore, it has the smallest value of $pK _\alpha$. Similarly, the oxidation number of chlorine in $HClO$ is the lowest because it has the least number of oxygen atoms. Hence its acidic strength is the least, and so its $pK _\alpha$ is the highest.

$HCl$ is soluble in organic solvents such as benzene and toluene.

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

HCl is a covalent compound which dissociates to form hydrogen and chloride ions. Benzene and toluene undergo electrophilic aromatic substitution reaction when chloride ion binds to the benzene ring forming aryl halides.

When manganese dioxide is treated with $HCl$,oxidation state of chlorine on the product side is:

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. $-1$

  2. $0$

  3. $+1$

  4. $+3$

Show answer
Correct Option: A,B
Explanation:

$Mn{ O } _{ 2 }+4HCl\longrightarrow Mn{ Cl } _{ 2 }+{ Cl } _{ 2 }$
Oxidation state of $Cl$ on the product side is $-1,0$

Which of the following is a good conductor of electricity?

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. Anhydrous $HCl$

  2. Aqueous $HCl$

  3. $HCl$ gas

  4. Crystalline $HCl$

Show answer
Correct Option: B
Explanation:

Aqueous $HCl$ is ionized as $H^{+},Cl^{-}$ which allows the electricity to flow  where as all other $HCl$ is available as unionized form which do not allow the electricity to pass.
Hence option $B$ is correct.

When carbonates are reacted with $HCl$, the gas evolved is:

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. $Cl _2$

  2. $CO _2$

  3. $O _2$

  4. $H _2$

Show answer
Correct Option: B
Explanation:

${ Na } _{ 2 }C{ O } _{ 3 }+HCl\longrightarrow NaCl+{ H } _{ 2 }O+C{ O } _{ 2 }$
Carbonates reacts with $HCl$ gives $C{ O } _{ 2 }$

Molecule mass of HCl is :

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. $22.8$ g

  2. $36.5$ g

  3. $28$ g

  4. $51$ g

Show answer
Correct Option: B
Explanation:

M.W. of $H$ $=1$ g 
M.W. of $Cl$ $=35.5$ g 

So, $1+35.5$ g$=36.5$ g

Spirit of salt is the other name of :

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. hydrochloric acid

  2. sulphuric acid

  3. nitric acid

  4. hydroiodic acid

Show answer
Correct Option: A
Explanation:

Hydrochloric acid is a clear, colorless, highly pungent solution of hydrogen chlorine in water. It is also known as spirit of salt and muriatic acid.

The metal that cannot displace hydrogen from dilute hydrochlocric acid is 

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. aluminium

  2. iron

  3. copper

  4. zinc

  5. magnesium

Show answer
Correct Option: C

Name the ion(s) obtained when $HCl$ dissociates in aqueous solution.

chemistry p- block elements-ii hydrogen chloride chlorine - 17 group p-block elements

  1. ${ H } _{ 3 }{ O }^{ + }$

  2. ${ Cl }^{ - }$

  3. Both $A$ and $B$

  4. None of these

Show answer
Correct Option: C
Explanation:

Acidic nature of $HCl$ is due to hydrogen ions which reacts with water to form hydronium ions. 
$HCl(g) +{ H } _{ 2 }O \rightleftharpoons { H } _{ 3 }{ O }^{ + }+{ Cl }^{ - }$