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Questions Related to chemistry

Equations relating to acidic properties of an aq. solution of HCl gas is/are :

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

  1. $HCl\left( g \right) +{ H } _{ 2 }O\rightleftharpoons { H } _{ 3 }{ O }^{ + }+{ Cl }^{ - }$

  2. $Zn\left( OH \right) _{ 2 }+2{ H }Cl\rightarrow { ZnCl } _{ 2 }+2{ H } _{ 2 }O$

  3. $ { MnO } _{ 2 }+4HCl\rightarrow { MnCl } _{ 2 }+{ Cl } _{ 2 }+2{ H } _{ 2 }O$

  4. all of the above

Show answer
Correct Option: D
Explanation:

1) $HCl\left( g \right) +{ H } _{ 2 }O\rightleftharpoons { H } _{ 3 }{ O }^{ + }+{ Cl }^{ - }$
2) ${ 2KMnO } _{ 4 }+16HCl\rightarrow { 2MnCl } _{ 2 }+{ 8H } _{ 2 }O+2KCl+{ 5Cl } _{ 2 }$
3) $ { MnO } _{ 2 }+4HCl\rightarrow { MnCl } _{ 2 }+{ Cl } _{ 2 }+2{ H } _{ 2 }O$
4) $Zn\left( OH \right) _{ 2 }+{ H }Cl\rightarrow { ZnCl } _{ 2 }+{ H } _{ 2 }O$

All of the above equation shows the acidic properties of hydrochloric acid.

Which of the following has pungent odour?

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

  1. $H _2SO _4$

  2. $CH _3COOH$

  3. HCl

  4. Both (a) and (b)

Show answer
Correct Option: C
Explanation:

Hydrochloric acid has a pungent smell and is a colourless gas.

    Appearance  Reaction with dilute $HCl$  Reaction with dilute $HNO _3$
 Unknown metal #1  Dull gray solid with white oxide coating Dissolved with bubbles of clear gas   Dissolved with bubbles of clear gas
 Unknown metal #2  Solid; lustrous, smooth silver-gray surface  No reaction  Dissolved with bubbles of orange gas

Identify metal #1.

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

  1. Mercury

  2. Copper

  3. Zinc

  4. Iron

  5. Silver

Show answer
Correct Option: C
Explanation:

 Zinc being an active metal readily reacts with hydrochloric acid at room temperature to form soluble zinc chloride and hydrogen.

   $Zn+2{ H }Cl\rightarrow Zn{ Cl } _{ 2 }+{ H } _{ 2 }$
Zinc reacts with dilute nitric acid  and libreates nitric oxie.
$3Zn+{ 8HNO } _{ 3 }\rightarrow { 3Zn(NO _{ 3 }) } _{ 2 }+4{ H } _{ 2 }O+2NO$

Statement I : The reactivity of powdered zinc will be greater than the larger piece of zinc of the same mass with $\displaystyle HCl$.
Statement II : The larger piece of zinc of the same mass has more surface area than the powdered zinc.

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

  1. True, False

  2. False, True

  3. True, True

  4. False, False

Show answer
Correct Option: A
Explanation:

Statement I : The reactivity of powdered zinc will be greater than the larger piece of zinc of the same mass with HCl.
Statement II : The  powdered zinc has more surface area than the larger piece of zinc of the same mass. Higher is the surface area, higher is the reactivity.

Which of the following is produced by the reaction of zinc metal, $Zn$ and hydrochloric acid, $HCl$?
I. $H _2(g)$
II. $Cl _2(g)$
III. $Zn^{2+}(aq)$

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

  1. II only

  2. III only

  3. I and II only

  4. I and III only

  5. I, II, and III

Show answer
Correct Option: D
Explanation:

$\displaystyle H _2$ and $\displaystyle Zn^{2+}$ is produced by the reaction of zinc metal, $Zn$, and hydrochloric acid, $HCl$.
$\displaystyle Zn + 2HCl  \rightarrow ZnCl _2 + H _2$

The addition of dilute $HCl$ to unknown metal produced a transparent gas. What is the likely identity of this gas?

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

  1. $Cl _{2}$

  2. $H _{2}$

  3. $O _{2}$

  4. $CO _{2}$

  5. $NO _{2}$

Show answer
Correct Option: B
Explanation:

Metals that come before hydrogen in the reactivity series form their corresponding chlorides when heated with HCl and liberate hydrogen gas.

Eg:
$Ca+2HCl\rightarrow { CaCl } _{ 2 }+{ H } _{ 2 }$


| |  Appearance |  Reaction with dilute $HCl$ |  Reaction with dilute $HNO _3$ | | --- | --- | --- | --- | |  Unknown metal #1 |  Dull gray solid with white oxide coating | Dissolved with bubbles of clear gas  |  Dissolved with bubbles of clear gas | |  Unknown metal #2 |  Solid; lustrous, smooth silver-gray surface |  No reaction |  Dissolved with bubbles of orange gas |

Identify metal #2.

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

  1. Carbon

  2. Copper

  3. Zinc

  4. Sodium

  5. Silver

Show answer
Correct Option: E
Explanation:

Silver has a lustrous smooth gray surface.

It reacts with $HNO _3$ as:
$3Ag+2{ HNO } _{ 3 }\rightarrow { 4AgNO } _{ 3 }+{ NO } _{ 2 }+{ H } _{ 2 }O$.
The orange gas obtained is $NO _2$.

$CaO(s)+H _3O^++Cl^-\longrightarrow$
Addition of solid calcium oxide to a solution of hydrochloric acid as given, results in the formation of:
(1) $Ca^{2+}$
(2) $H _2O$
(3) $H _2$

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: B
Explanation:

$CaO+2HCl \rightarrow CaCl _2+H _2O$

In this reaction, due to water, quick lime is converted into slaked lime, which on reaction with hydrochloric acid gives calcium chloride and water.


 Appearance  Reaction with dilute $HCl$  Reaction with dilute $HNO _3$
 Unknown metal #1  Dull gray solid with white oxide coating Dissolved with bubbles of clear gas   Dissolved with bubbles of clear gas
 Unknown metal #2  Solid; lustrous, smooth silver-gray surface  No reaction  Dissolved with bubbles of orange gas

Identify the orange gas produced on the addition of dilute $HN{O} _{3}$ to unknown metal #2.

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

  1. ${Cl} _{2}$

  2. ${H} _{2}$

  3. ${O} _{2}$

  4. $C{O} _{2}$

  5. $N{O} _{2}$

Show answer
Correct Option: E
Explanation:

Silver has a lustrous smooth gray surface.

It reacts with $HNO _3$ as;
$3Ag+2{ HNO } _{ 3 }\rightarrow { 4AgNO } _{ 3 }+{ NO } _{ 2 }+{ H } _{ 2 }O$.
Thus the orange gas produced is $NO _2$.

   Appearance   Reactions with dilute$HCl$ Reaction with Dilute$HNO _3$ 
 Unknown metal 1  Dull grey solid with white oxide coating  Dissolved with bubbles of clear gas  Dissolved with bubbles of clear gas
 Unknown metal 2  Solid, lustrous, smooth silver-grey surface  No reaction   Dissolved with bubbles of orange gas

Identify the gas(transparent) produced with the addition of dilute $HCl$ to unknown metal 1.

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

  1. ${Cl} _{2}$

  2. ${H} _{2}$

  3. ${O} _{2}$

  4. $C{O} _{2}$

  5. $N{O} _{2}$

Show answer
Correct Option: B
Explanation:

Metals reacts with $HCl$ to liberate hydrogen gas.