Tag: p-block elements

Questions Related to p-block elements

$CaO(s)+H _3O^++Cl^-\longrightarrow$
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.

The concentrated $HCl$ acid strongly fumes in_________.

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

  1. air

  2. water

  3. both

  4. none of these

Show answer
Correct Option: A
Explanation:

Concentrated hydrochloric acid fumes in the air forming acidic mists. Both the mist and the solution have a corrosive effect on human tissue with the potential to damage respiratory organs, eyes, skin and intestines.

All metals on reaction with $HCl$ liberate $H _{2}$ gas.

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

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Hydrochloric acid is used in chemical analysis to prepare sample for analysis. Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas but it does not react with all metals.

The boiling point of the hydrochloric acid varies with its concentration.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Physical properties of $HCl$ acid such as boiling point and melting points, density and pH depend upon the concentration or molarity of $HCl$ in the aqueous solution. They range from those of water at very low conc. approaching 0% $HCl$ to values for fuming $HCl$ over 40% $HCl$.

Which of the following is used to prepare $Cl _{2}$ gas at room temperature from concentrated $HCl$?

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $MnO _{2}$

  2. $H _{2}S$

  3. $KMnO _{4}$

  4. $Cr _{2}O _{3}$

Show answer
Correct Option: A,C
Explanation:

Manganese dioxide($MnO _2$) is heated with concentrated $HCl$ to form $Cl _2$

$MnO _2+4HCl\rightarrow MnCl _2+Cl _2+2H _2O$

 $HCl$ in action with potassium permanganate gives $C _2$

$2KMnO _4+16HCl\rightarrow 2KCl+2MnCl _2+8H _2O+5Cl _2$.

Hence option A and C is correct.

Which of the following statements is not correct?

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. All the oxides of halogens are powerful oxidants.

  2. The compounds of oxygen and fluorine are not called oxides but fluorides.

  3. Oxygen fluorides form oxoacids.

  4. In oxyhalides, bonds are mainly covalent due to small difference in electronegativity of oxygen and halogens.

Show answer
Correct Option: C
Explanation:

Oxygen florides forms $HF,O _2$ on hydrolysis.

$OF _2 + H _2O\rightarrow O _2 + 2 HF$

$2O _2F _2 + 2H2O\rightarrow O _2 + 4HF$

so oxygen florides do not form forms hypohalous acids.

So the given statement oxygen florides forms oxoacids is wrong.

Hence option C is correct.

Bleaching powder and bleach solution are produced on a large scale and is used in several house-hold products. The effectiveness of bleach solution is often measured by iodometry. Bleaching powder contains a salt of an oxoacid as one of its components. The anhydride of that oxoacid is:

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. $Cl _{2}O$

  2. $Cl _{2}O _{7}$

  3. $ClO _{2}$

  4. $Cl _{2}O _{6}$

  5. $Cl _2O _3$

  6. $Cl _2O _5$

  7. $Cl _3O _9$

  8. $Cl _3O _5$

Show answer
Correct Option: A
Explanation:

Bleaching powder is $Ca(OCl)Cl$.


So, bleaching powder contains a salt of $HOCl$.

$Cl _2O$ is an anhydride of $HOCl$.

$Cl _2O+H _2O\Rightarrow 2HOCl$.

Hence, option A is correct.

Hypo chlorite radical is represented as $(HClO _2)^{-1}$.

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Hypochlorite radical is represented as $ClO^-$. Thus the given statement is false.