Tag: bio-chemistry

Questions Related to bio-chemistry

Which of the following nutrient is absorbed by the active absorption?

  1. Amino acids

  2. Glucose

  3. Fatty acids

  4. Both A and B


Correct Option: D
Explanation:
Absorption is a process by which the end products of digestion pass from the alimentary canal into the blood and lymph through intestinal mucosa. It is carried out by the passive, active and facilitated type of transport mechanism.
Active transport mechanism occurs against the concentration gradient and is involved in the absorption of amino acids, monosaccharides like glucose, and electrolytes like Na+.
So the correct answer is 'Both A and B'.

Fats are mostly absorbed in

  1. Duodenum

  2. Jejunum

  3. Ileum

  4. Both A and B


Correct Option: D
Explanation:
The small intestine is the main site for absorption of nutrients and digestion of fat. Fats are consist of glycerol and fatty acids. They are mostly absorbed in duodenum and jejunum part of the small intestine. Duodenum is the upper portion of the intestine that gives hormonal signal whereas jejunum has microvilli that help in increasing the surface area for the absorption of fats.
So the correct answer is 'Both A and B'.

Minerals associated with  redox reactions are

  1. Na, Cu

  2. N, Cu

  3. Fe, Cu

  4. Ca, Fe


Correct Option: C

Which of the following is a redox reaction?

  1. $C{ a }CO _{ 3 }\quad \rightarrow \quad { { C }{ a }O+{ CO } _{ 2 } }$

  2. $H _{ 2 }+Cl _{ 2 }\quad \rightarrow \quad 2HCl$

  3. ${ C }{ a }O+2HCl\quad \rightarrow \quad { C }{ a }{ Cl } _{ 2 }+{ H } _{ 2 }O$

  4. ${ N }{ a }OH+HCl\quad \rightarrow \quad { N }{ a }{ Cl }+{ H } _{ 2 }O$


Correct Option: A

Which reaction is not a redox reaction?

  1. $Mg+2HNO _3\rightarrow Mg(NO _3) _2+H _2$

  2. $2Mg(NO _3) _2\rightarrow 2MgO+4NO _2+O _2$

  3. $SO _2+NO _2\rightarrow SO _3+NO$

  4. $SO _3+H _2O\rightarrow H _2SO _4$


Correct Option: C

How many moles of electrons are involved in the reduction of one mole of $MnO^- _4$ ion in alkaline medium to $MnO^- _3$?

  1. $2$

  2. $1$

  3. $3$

  4. $4$


Correct Option: A
Explanation:
Reaction takes place as follows:
$Mn{ O } _{ 4 }^{ - }+{ H } _{ 2 }O+{ 2e }^{ - }\rightarrow Mn{ O } _{ 3 }^{ - }+2O{ H }^{ - }$
So, 2 electrons are involved in reduction of 1 mole of ${MnO} _4^{-}$ ion in alkaline medium to ${MnO} _3^{-}$.

In acid medium, the standard reduction potential of $NO$ converted to ${ N } _{ 2 }O$ is $1.59 V$. Its standard potential in alkaline medium would be:

  1. $-1.59 V$

  2. $-0.764 V$

  3. $0.764 V$

  4. $0.062 V$


Correct Option: C
Explanation:

$NO \longrightarrow N _2O$      $E^o= 1.59V$

The reaction in acidic medium,
$2NO+2H^+ \longrightarrow N _2O+H _2O$;   $E^o=1.59$
In basic medium,
$2NO+H _2O \longrightarrow N _2O+2OH^-$;   Let $E^o=x$
Now, in alkaline medium,
$H _2O \rightleftharpoons H^++OH^-$
$\Rightarrow K=10^{-14}$
or, $2H _2O \rightleftharpoons 2H^++2OH^-$,   $K= 10^{-28}$
We know, $E^o= \cfrac {0.059}{n}\log K$
$=\cfrac {0.059}{2}\log 10^{-28}= 0.826$
For standard potential,
$E^o _{acidic}+E^o _{basic}=E^o _{cell}$
$\Rightarrow 1.59+x= 0.826$
$\Rightarrow x= 0.764$

A solution contains ${Fe}^{+2},{Fe}^{+3}$ and ${I}^{-}$ ions. This solution was treated with iodine at ${35}^{o}C$. Then the favourable redox reaction is: 

(Given that ${ E } _{ { Fe }^{ +3 }/{ Fe }^{ +2 } }^{ o }=+0.77V;\quad { E } _{ { I } _{ 2 }/{ I }^{ - } }^{ o }=0.536V$)

  1. ${I} _{2}$ will be reduced to ${I}^{-}$

  2. there will be no redox reaction

  3. ${I}^{-}$ will be oxidised to ${I} _{2}$

  4. ${Fe}^{+}$ will be oxidised to ${Fe}^{+3}$


Correct Option: A
Explanation:

${ 2I }^{ - }\rightarrow { I } _{ 2 }+{ 2e }^{ - }(oxidation\quad half-reaction)$

${ E } _{ Oxidation }^{ 0 }=-0.536V$

${ Fe }^{ 3+ }+e^{ - }\rightarrow { Fe }^{ 2+ }(reduction\quad half-reaction)$

$E^{ 0 } _{ Reduction }=-0.77V$
----------------------------------------------------------------------------------------------------------------------
${ 2Fe }^{ 3+ }+{ 2I }^{ - }\rightarrow { 2Fe }^{ 2+ }+{ I } _{ 2 }$

$E^{ 0 }={ E } _{ oxidation }^{ 0 }+E _{ Reduction }^{ 0 },+ve$

Hence the reaction will take place.

${ 2I }^{ - }\rightarrow { I } _{ 2 }+{ 2e }^{ - }(oxidation\quad half-reaction)$

${ E }^{ 0 } _{ Oxidation }=-0.536V$

${ Fe }^{ 3+ }+{ e }^{ - }\rightarrow { Fe }^{ 2+ }(reduction\quad half-reaction)$

$E _{ Reduction }^{ 0 }=-0.77V$
------------------------------------------------------------------------------------------------------------------------
$2Fe^{ 3+ }+{ 2I }^{ - }\rightarrow { 2Fe }^{ 2+ }+{ I } _{ 2 };$

${ E }^{ 0 }={ E } _{ oxidation }^{ 0 }+{ E } _{ reduction }^{ 0 };+ve$

$HOCl(aq)$ is the molecule that kills bacteria wen chlorine is added to water. 
The following reaction produces this molecule
${Cl} _{2}(g)+{H} _{2}O(l)\rightleftharpoons HOCl(aq)+{H}^{+}(aq)+{Cl}^{-}(aq)$
Which statement about this reaction is correct?

  1. Chlorine is both oxidised and reduced

  2. Chlorine is oxidised but not reduced

  3. Hydrogen is both oxidised and reduced

  4. Hydrogen is oxidised but not reduced


Correct Option: A
Explanation:

Oxidation and reduction are two types of chemical reactions that often work together. Oxidation and reduction reactions involve an exchange of electrons between reactants.

  • Reduction and oxidation occur simultaneously in a type of chemical reaction called a reduction-oxidation or redox reaction.
  • Oxidation Involves Loss of electrons
  • Reduction Involves Gain of electrons.
As we can see the above case with the chlorine .
hence chlorine is both oxidised and reduced

Which of the following reaction is non-redox?

  1. $2NaNO _{3}\rightarrow 2NaNO _{2}+O _{2}$

  2. $CaO+SiO _{2}\rightarrow CaSiO _{3}$

  3. $Fe+H _{2}SO _{4}\rightarrow FeSO _{4}+H _{2}$

  4. $4Ag+8CN^{-}+O _{2}+2H _{2}O\rightarrow 4[Ag(CN) _{2}]^{-}+4OH^{-}$


Correct Option: B