Tag: acids and bases

Questions Related to acids and bases

Which of the following is least basic?

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. NF3N

  2. NH3

  3. NCl3

  4. NI3

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Correct Option: A

In which case of mixing a strong acid and a base each of $1$N concentration, temperature rise is highest?

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. $20$ ml, acid + $30$ ml alkali

  2. $10$ ml, acid + $40$ ml alkali

  3. $20$ ml, acid + $20$ ml alkali

  4. $30$ ml, acid + $20$ ml alkali

Show answer
Correct Option: C
Explanation:

More amount of acid reacts with equal amount of base, higher the amount of heat releases.

So, $20ml$ of acid+$20ml$ of alkali.

Conjugate base of ${ H } _{ 3 }{ PO } _{ 4 }$?

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. ${ H } _{ 2 }{ PO } _{ 4 }^{ - }$

  2. ${ H } _{ }{ PO } _{ 4 }^{ 2- }$

  3. ${ H } _{ 4 }{ PO } _{ 4 }^{ + }$

  4. ${ H } _{ 3 }{ PO } _{ 4 }^{ }$

Show answer
Correct Option: A
Explanation:

${H _2PO _4}^-$ is conjugate base of $H _3PO _4$  .

$H _2O _2$ is a:

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. monobasic acid

  2. dibasic acid

  3. neutral compound

  4. weal alkali

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Correct Option: B
Explanation:
A dibasic molecule has two replaceable hydrogen atoms. Since $H _2O _2$ has two replaceable hydrogen atoms, That's why it is a dibasic acid.

$H _2O _2\rightarrow HO _2^−+H^+$

$HO _2^−\rightarrow O _2^{−2}+H^+$


$\mathbf{Hence\ the\ correct\ answer\ is\ option\ (B)}$

The chloride salt of a certain weak monoacidic organic base is hydrolysed to an extent of $3$% in its $0.1M$ solution at ${25}^{o}C$. Given that the ionic product of water is ${10}^{-14}$ at this temperature, what is the dissociation constant of the base?

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. $\approx 1\times { 10 }^{ -10 }$

  2. $\approx 1\times { 10 }^{ -9 }$

  3. $\approx 3.33\times { 10 }^{ -9 }$

  4. $\approx 3.33\times { 10 }^{ -10 }$

Show answer
Correct Option: A
Explanation:

$h = 0.03$, $C = 0.1 M$ , $K _{w} = 10^{-14}$       

We know, $K _{a} = Ch^{2}   $
$\cfrac{K _{w}}{K _{b}} = Ch^{2}    \Rightarrow \cfrac{10^{-14}}{K _{b}} = (0.1)(0.03)^{2} \Rightarrow  \cfrac{10^{-9}}{9} \approx 1 \times 10^{-10}$

A mixture containing one mole of $BaCl _2$ and two moles of $H _2SO _4$ will be neutralized by:

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. $1$ mole KOH

  2. $4$ mole KOH

  3. $2$ mole KOH

  4. $1$ mole Ca(OH)$ _2$

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Correct Option: B

Baking soda turns:

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. turmeric to red

  2. purple-cabbage juice to green

  3. red litmus to blue

  4. all of the above

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Correct Option: D
Explanation:

Turmeric, purple cabbage juice (containing anthocyanin), and litmus paper all act as indicators which help us to detect whether a particular substance is acidic or basic.

In basic medium, turmeric changes it's colour to red, purple-cabbage juice turns to green and red litmus turns to blue.
Baking soda/Sodium carbonate $Na _2CO _3$ is basic in nature and thus causes the above changes in the indicators.
Hence, the correct answer is option (D).

China rose indicator is turned green by a certain solution. The solution is:

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. acidic

  2. basic

  3. neutral

  4. all of these 

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Correct Option: B
Explanation:

An indicator is usually a weak acid or a weak base which changes colour in acidic or basic solutions.  The pigment anthocyanin present in the china rose flower makes its solution an indicator.
China rose solution gives dark pink colour with acid and green colour with base.

Which of the following equation represents action of alkali on aluminium oxide?

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. $Al _2O _3+2NaOH\rightarrow2NaAlO _2+H _2O$

  2. $Al _2O _3+2KOH\rightarrow2KAlO _2+H _2O$

  3. $Al _2O _3+KOH\rightarrow KAlO _2+H _2O$

  4. Both A and B

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Correct Option: D
Explanation:

$Al _2O _3+KOH\rightarrow KAlO _2+H _2O$ 

Oxides and hydroxides of certain metals are ________ in nature.

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. Acidic

  2. Amphoteric

  3. Basic

  4. Neutral

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Correct Option: B
Explanation:

Oxides and hydroxides of certain metals are amphoteric in nature.