Tag: p- block elements-ii

Questions Related to p- block elements-ii

$10 ml$ of chlorine gas and $25 ml$ of Oxygen gas reacts to form?

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

Show answer
Correct Option: D

The oxidation state of chlorine in chlorous acid is:

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry
    • 2
    • 3
    • 1
    • 2
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Correct Option: B
Explanation:

Chlorous acid = $\overset{+1\ +3\ -4}{HClO _{2}}$
Let oxidation state of chlorine be x.
$\therefore{x}+1+2(-2)=0$
Here oxidation state of oxygen is -2 and that of hydrogen is +1.
$\therefore x=+3$
oxidation state in chlorous acid of chlorine is +3.

The oxidation number of chlorine in KClO is:

oxoacids of halogens p- block elements-ii p-block elements the p-block elements chemistry
    • 1
    • 3
    • 5
    • 7
Show answer
Correct Option: A
Explanation:

$\overset{+1}{K}Cl\overset{-2}{O}$
oxidation state of alrali metals = +1
oxygen = -2

Let oxidation state of chlorine is x.
$\therefore$ x+1+(-2) = 0
$\therefore$ x = +1 
Thus, oxidation state of chlorine in potassium chlorate is +1.

Chemically bleaching powder is called:

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

  1. Calcium oxychloride

  2. Calcium chlorohypochlorite

  3. Calcium monooxygen chloride

  4. Calcium oxygen dichloride

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Correct Option: B
Explanation:


Bleaching powder is also called calcium chlorohypochlorite because it is considered as a mixed salt of hydrochloric acid and hypochlorous acid. 


Option B is correct.

The oxidation state of Chlorine in Bleaching Powder:

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

  1. -2

    • 1
    • 1

  4. -1 and + 1

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Correct Option: D
Explanation:

The chemical formula of bleaching powder is $CaOCl _{2}$. Here, calcium is bonded to $Cl^{-}$ ion and $OCl^{-}$ ion respectively.

In $Cl^{-}$ the oxidation state of chlorine is -1 and in $OCl^{-}$ ion the oxidation state of chlorine is +1.

The chemical formula of the oxyacid of chlorine in which chlorine exhibits its highest oxidation state is:

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

  1. $HOCl$

  2. $HClO _2$

  3. $HClO _3$

  4. $HClO _4$

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Correct Option: D
Explanation:

$HCIO _4$ has highest oxidation state of chlorine i.e + 7

The two acids present in Chlorine water are:

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

  1. HCl, $H _2SO _4$

  2. HCl, $HNO _3$

  3. HCl, HOCl

  4. HCl, $HClO _4$

Show answer
Correct Option: C
Explanation:

Chlorine water
$CI _2+H _2O \rightarrow HOCI+HCI$

Chlorine does not support combustion.

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

  1. True

  2. False

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Correct Option: B
Explanation:

Chlorine supports vigorous combustion of many elements to form their chlorides.

Which has maximum pH in aqueous solution ? 

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

  1. $NaClO$

  2. $NaClO _2$

  3. $NaClO _3$

  4. $NaClO _4$

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Correct Option: A
Explanation:

$NaClO$ has the maximum $pH$ because the acidic strength decreases with decreasing $O$ atoms in oxy acids . Since $NaClO$ has the lowest oxygen atom among given options, it will have least acidic strength and hence, a maximum $pH$.

Which one of the following anions can undergo both oxidation and reduction?

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

  1. $Cr _2{O _7}^{2-}$

  2. $N{O _3}^{-}$

  3. $OCl^-$

  4. ${S}^{2-}$

Show answer
Correct Option: C
Explanation:

$(A)$ In $Cr _2{O _7}^{2-}$, the oxidation state of $Cr$ is $+6$, which is maximum oxidation of $Cr$. It can only lower down its oxidation state. So, it acts only as an oxidising agent.
$(B)$ In $N{O _3}^{-}$, the oxidation state of $N$ is $+5$, which is the maximum oxidation of $N$. It can only lower its oxidation state  and so, it acts only as an oxidising agent.
$(C)$ In $OCl^-$, the oxidation state of $Cl$ is $+1$ and $Cl$ shows oxidation state from $-1$ to $+7$ and so, it can undergo both oxidation and reduction.
$(D)$ In ${S}^{2-}$, the oxidation state of $S$ is $-2$, which is the minimum oxidation state of $S$ and so, it can only increase its oxidation state and hence, it acts only as a reducing agent.

Therefore, $OCl^-$ can undergo both oxidation as well as reduction.