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Multiple choice salts salts and their classification acids, bases and salts chemistry

Equal volumes of $1\ M$ $HCl$ and $1\ M$ $H _2SO _4$ are neutralized by dilute NaOH solution liberating $x$ kcal and $y$ kcal heat. Which of the following is correct?

  1. $x=y$
  2. $x=0.5y$
  3. $x=0.4y$

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Reaction involved are:
$HCl+NaOH \rightarrow NaCl+H _2O, \Delta H _1=xkcal$
$H _2SO _4+2NaOH \rightarrow Na _2SO _4+2H _2O, \Delta H _1=ykcal$
(i) acid-base neutralization reaction for HCl is represented as:
$H^++OH^- \rightarrow H _2O, \Delta H _1=xkcal$
(ii) acid-base neutralization reaction for $H _2SO _4$ is represented as:
$2H^++2OH^- \rightarrow 2H _2O, \Delta H _1=ykcal$
since reaction (ii) is twice of reaction (i), so is the enthalpies
thus $2x=y$
or $x=0.5y$
Multiple choice salts salts and their classification acids, bases and salts chemistry

Which of the following salts is most basic in aqueous solution?

  1. ${\text{C}}{{\text{H}} _{\text{3}}}{\text{COOK}}\,$
  2. ${\text{FeC}}{{\text{l}} _{\text{3}}}\,\,$
  3. ${\text{Pb(C}}{{\text{H}} _{\text{3}}}{\text{COOK}}{{\text{)}} _{\text{2}}}\,$
  4. ${\text{Al}}{\left( {{\text{CN}}} \right) _{\text{3}}}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CH3COOK is a salt of a weak acid (acetic acid) and a strong base (potassium hydroxide). In aqueous solution, the acetate ion undergoes hydrolysis to form OH- ions, making the solution basic. The other options involve salts of strong acids or weak bases, which result in acidic or neutral solutions.

Multiple choice salts salts and their classification acids, bases and salts chemistry

A and B are two salts. A with dil. HCI and A and B with conc. ${H _2}S{O _4}$react to give reddish brown vapours, hence A and B respectively are:

  1. $NaN{O _3},NaBr$
  2. $NaBr,NaN{O _3}$
  3. $NaBr,NaN{O _2}$
  4. $NaN{O _{2,}}NaBr$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bromide salts (NaBr) react with conc. H2SO4 to produce reddish-brown bromine vapors. Nitrates (NaNO3) react with conc. H2SO4 to produce reddish-brown NO2 gas upon heating. Since A reacts with dil. HCl, it must be the bromide (as nitrates do not react with dil. HCl).

Multiple choice salts salts and their classification acids, bases and salts chemistry

In the reaction, $BaCl _{2}(aq)+K _{2}SO _{4}(aq)\rightarrow BaSO _4(s)+2KCl(aq)$, which is not a spectator ion?

  1. $K^{+}$
  2. $Cl^{-}$
  3. $Ba^{2+}$ and $SO _{4}^{-2}$
  4. Both $A$ and $B$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ions that are not involved in the formation of insoluble solid are called as spectator ions.


Therefore, $Ba^{2+}$ and $SO _{4}^{2-}$ ions form insoluble solid.

Hence they are not spectator ions.


Option C is correct.

Multiple choice salts salts and their classification acids, bases and salts chemistry

Which of the following methods is generally used for preparing $Zn(NO _3) _2$ salt?


1 : Neutralisation - insoluble base & dilute acid  
2 : Neutralisation - alkali & dilute acid      

3 : Simple displacement - active metal & dilute acid  
4 : Direct combination                     

5 : Precipitation [double decomposition]

  1. 2

  2. 3

  3. 4

  4. 5
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Zinc metal with dilute nitric acid gives zinc nitrate.

So, simple displacement-active metal & dilute acid is the correct option for this.

$Zn+2HNO _3 \rightarrow Zn(NO _3) _2+H _2$

Hence, the correct option is $(B)$.

Multiple choice salts salts and their classification acids, bases and salts chemistry
State which of the following methods is generally used for preparing the $FeS$ salts
1: Neutralisation-insoluble base & dilute acid.
2: Neutralisation-alkali & dilute acid.
3: Simple displacement-active metal & dilute acid.
4: Direct combination.
5: Precipitation [double decomposition].

  1. 1

  2. 2

  3. 3

  4. 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation


Iron(II) sulfide is obtained by heating of iron and sulfur which is a direct combination.
$Fe+S \longrightarrow FeS$


Hence, the correct option is $(D)$

Multiple choice salts salts and their classification acids, bases and salts chemistry
State which of the following methods is generally used for preparing the $Cu(NO _3) _2$ salts.
1: Neutralisation-insoluble base & dilute acid.
2: Neutralisation-alkali & dilute acid.
3: Simple displacement-active metal & dilute acid.
4: Direct combination.           
5: Precipitation [double decomposition].

  1. 1

  2. 2

  3. 3

  4. 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Copper reacts with nitric acid to form copper nitrate.


$3Cu+8HNO _3 \rightarrow 3Cu(NO _3) _2+4H _2O+2NO$

Hence, the correct option is simple displacement-active metal & dilute acid.  


Hence, the correct option is $(C)$

Multiple choice salts salts and their classification acids, bases and salts chemistry

The best indicator for the detection of end point in titration of a weak acid and a strong base is :

  1. methyl orange (3 to 4)

  2. methyl red (5 to 6)

  3. bromothymol blue (6 to 6.5)

  4. bromothymol blue (6 to 7.5)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

BTB is a pH indicator for reactions between weak acids and bases. It is mostly used in applications that require measuring substances that have a pH near 7. It can be protonated or deprotonated appearing yellow or blue. It is bluish green in neutral solution.