Tag: chemical properties

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Questions Related to chemical properties

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

$PhCOOH\xrightarrow{DIBALH} $ 

  1. $PhCHO$
  2. $PhO$
  3. $PhCH _2OH$

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Benzoic acid on reduction with di-isobutyl aluminium hydride (DIBALH) gives benzaldehyde.
$\displaystyle PhCOOH \xrightarrow {DIBALH} PhCHO $
Di-isobutyl aluminium hydride (DIBALH) is a reducing agent. It reduces carboxylic acids to aldehydes.

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

How  - $COOH$ can be converted into $CH _3$ group?

  1. $\;Na\;\&\;alcohol$
  2. $\;Zn+HCl$
  3. $\;LiAlH _4$
  4. $\;Hl\;\&\;red\;phosphorous$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$-COOH$ can be converted into $CH _3$ group by heating with a mixture of HI and red phosphorus.
$CH _3COOH  \xrightarrow {\;Hl\;&\;red\;phosphorous} CH _3-CH _3$

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

Which of the following reaction is not the oxidation?

  1. $CH _{3} - CHO \rightarrow CH _{3}COOH$
  2. $C _{2}H _{5}OH \rightarrow CH _{3} - CHO$
  3. $C _{2}H _{5}OH \rightarrow CH _{3} - COOH$
  4. $CH _{3}COOH \rightarrow C _{2}H _{5}OH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oxidation involves the loss of electrons or an increase in oxidation state (often adding oxygen or removing hydrogen). Option D shows the reduction of acetic acid to ethanol (adding hydrogen), which is the opposite of oxidation.

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

$CH _{3}COOH \xrightarrow[]{LiAlH _{4}}(A)\xrightarrow[H _{2}]{Ni} B$ In this reaction A and B respectively are :

  1. $CH _{3}OH and CH _{4}$
  2. $C _{2}H _{5}OH and C _{2}H _{6}$
  3. $CH _{3}CHO and C _{2}H _{5} OC _{2}H _{5}$
  4. $C _{2}H _{5}OH and CH _{3}OCH _{3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

B
$LiAlH _{4}$ reduces ethanoic acid to ethanol and then $H _{2}$ / Ni reduces it further to alkane.

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

The reagent(s) used for converting ethanoic acid to ethanol is/are :

  1. $LiAlH _{4}$
  2. $BH _{3}$ in $THF$
  3. $PCl _{3}$
  4. $K _{2}Cr _{2}O _{7}/H^{+}$
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

$BH _3$ in $THF$ being a strong reducing agent, can efficiently convert carboxylic acid into the corresponding primary alcohol. Also, $LiAlH _4$ being a strong reducing agent, releases $H^-$ ions in enough quantity to convert carboxylic acid to the corresponding alcohol. So, ethanoic acid can be converted to ethanol using $BH _3$ in $THF$ and $LiAlH _4$.

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

Methyl alcohol when reacted with carbon monoxide using cobalt or rhodium as catalyst , compound $'A'$ is formed. $'A'$ on heating with HI in the presence of red phosphorus as catalyst $'B'$ is formed. $'B'$ is:

  1. $CH _3COOH$
  2. $CH _3CHO$
  3. $CH _3CH _2I$
  4. $CH _3CH _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$CH _3OH+CO\xrightarrow [ (High\quad Pressure) ]{ CO/Rh } \underbrace{ CH _3COOH} _{Compound A}$

Alcohol with carbon monoxide in presence of  $CO/Rh$ gives carboxylic Acid.
$CH _3COOH\quad \underrightarrow{Red P+HI}\quad CH _3-CH _3$
$Red P+HI$  is areducing agent and reduces carboxylic acid into hydrocarbons.

Multiple choice chemistry alcohols, esters and carboxylic acids reduction of carboxylic acids chemical properties chemical properties of carboxylic acids

Alcohols can be obtained from carboxylic acids by reduction using one of the following reagents:

  1. $LiAIH _{4}$
  2. $N/alcohol$
  3. $Zn/HCl$
  4. $H _{2}/Ni$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$RCOOH  +  LiAlH _4 \rightarrow RCHO  \rightarrow RCH _2OH $

Carboxylic acids along with lithium aluminium hydride, initially gives aldehyde and then reduced to primary alcohols.