Tag: p-block elements

Questions Related to p-block elements

 $\displaystyle { HCl(g) }$ and $\displaystyle { HCl (aq) }$ have different behaviour towards litmus.

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

  1. True

  2. False

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Correct Option: A
Explanation:

$HCl$ can produce ions only in aqueous solution making aqueous $HCl$acidic. So, aqueous $HCl$ turns blue litmus red whereas dry $HCl$ does not dissociate and acts inert to litmus.

Aqua-regia dissolves gold. 
which is correct?

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

  1. Aqua regia, or nitro-hydrochloric acid is a highly corrosive mixture of acids , a fuming yellow or red solution.

  2. The mixtures is formed by freshly mixing concentrated nitric acid and hydrochloric acid hoptimally in a volume ratio of 1:3.

  3. it can dissolve the noble metalsgold and platinum

  4. all of these

Show answer
Correct Option: D
Explanation:

Aqua regia, or nitro-hydrochloric acid is a highly corrosive mixture of acids, a fuming yellow or red solution. The mixtures is formed by freshly mixing concentrated nitric acid and hydrochloric acid hoptimally in a volume ratio of 1:3. It was named so because it can dissolve the noble metalsgold and platinum
Hence answer 1 is correct.

What is the pH number of hydrochloric acid?

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

  1. Below 7

  2. Above 7

  3. 7

  4. Between 8 and 10

Show answer
Correct Option: A
Explanation:

The pH of acids is given by the pH scale from 1-7. Strength of acids increases by moving down the scale from 7 to 1. High acidity ranks as 1 on the pH scale and 7 are neutral. HCl is highly acidic so it has pH less than 7 while on this scale basicity increases going from 7 to 14. So all the acids have pH under 7.


Option A is correct.

What if hydrochloric acid comes in contact with a metal such as magnesium?

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

  1. Liberate $H _2$ gas

  2. Liberate $Cl _2$ gas

  3. Precipitate $Mg$

  4. No reaction will take place

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Correct Option: A

Which of the follwoing statements is correct?

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

  1. HCl is covalent both in aqueous solution and in the gaseous state

  2. HCl is covalent in the gaseous state but ionic in aqueous solution

  3. HCl is ionic both in the gaseous state and in aqueous solution

  4. None of the above

Show answer
Correct Option: B
Explanation:

HCl is covalent in the gaseous state but dissociates into ions in aqueous solution. It behaves like acid when aqueous.

Which one of the following substances is formed by the reaction of potassium permanganate on concentrated by hydrochloric acid?

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

  1. ${H} _{2}O _2$

  2. $HOCl$

  3. ${H} _{2}$

  4. ${Cl} _{2}$

Show answer
Correct Option: D
Explanation:
$2KMnO _4+16HCl \rightarrow 2KCl+2MnCl _2+8H _2O+5Cl _2$

A glass rod dipped in ammonia solution is brought near the mouth of the $HCl$ gas, then:

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

  1. deep red flame of ammonium chloride appears

  2. dense white fumes of ammonium chloride appears

  3. no reaction occurs

  4. none of the above

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Correct Option: B
Explanation:
When a glass rod dipped in the ammonia solution is brought near HCl gas, a dense white fume of ammonium chloride is formed.
This is because ammonia reacts with the fumes of $HCl$ to give ammonium chloride.
$NH _3 + HCl \rightarrow NH _4Cl$

A solution of hydrogen chloride gas was named as :

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

  1. blue vitriol

  2. green vitriol

  3. muriatic acid

  4. none of the above

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Correct Option: C
Explanation:
HCl was named initially as muriatic acid or spirits of salt because it was produced from rock salt and green vitriol.

$HCl$ occurs in:

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

  1. free state

  2. combined state

  3. Both A and B

  4. None of the above

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Correct Option: A
Explanation:

In the free state HCl gas is found in the trace amount in volcanic regions.

HCl is secreted as gastric juices in the stomach during digestion of food. 

A piece of zinc may be distinguished from a piece of magnesium by: 
(1) determining which conducts electricity
(2) determining which releases $H _2$ gas from a 1-molar hydrochloric acid solution
(3) measuring the density of each

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

  1. If 1, 2 and 3 are correct

  2. If only 1 and 2 are correct

  3. If only 2 and 3 are correct

  4. If only 1 is correct

  5. If only 3 is correct

Show answer
Correct Option: E
Explanation:

Both zinc and magnesium conduct electricity. Both zinc and magnesium reacts with hydrochloric acid to give hydrogen gas. They can be distinguished by measuring their densities.