Tag: bio-chemistry

Quizzes (82) Questions (1918)

Questions Related to bio-chemistry

Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

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

  1. Amino acids

  2. Glucose

  3. Fatty acids

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice bio-chemistry digestive system of human absorption mechanism absorption digestion

Fats are mostly absorbed in

  1. Duodenum

  2. Jejunum

  3. Ileum

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

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. ${ N }{ a }OH+HCl\quad \rightarrow \quad { N }{ a }{ Cl }+{ H } _{ 2 }O$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A redox reaction involves the change in oxidation states of atoms. In option B, elemental hydrogen and chlorine react to form hydrogen chloride, where hydrogen is oxidized from 0 to +1 and chlorine is reduced from 0 to -1. The other options represent thermal decomposition or double displacement reactions without changes in oxidation numbers.

Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

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. $SO _3+H _2O\rightarrow H _2SO _4$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A redox reaction is characterized by a change in the oxidation states of the reacting species. Option D is a combination reaction between sulfur trioxide and water to form sulfuric acid, where sulfur remains in the +6 oxidation state, oxygen remains in the -2 state, and hydrogen remains in the +1 state throughout. The other three options involve changes in oxidation states, making them redox processes.

Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

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. $4$
Reveal answer Fill a bubble to check yourself
A Correct answer
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 ${MnO} _3^{-}$.
Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

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. $0.062 V$
Reveal answer Fill a bubble to check yourself
C Correct answer
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,
$E^o _{acidic}+E^o _{basic}=E^o _{cell}$
$\Rightarrow 1.59+x= 0.826$
$\Rightarrow x= 0.764$

Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

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 ${Fe}^{+3}$
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

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

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

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

Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

$HOCl(aq)$ 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
Reveal answer Fill a bubble to check yourself
A Correct answer
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

Multiple choice bio-chemistry biological oxidation classical idea of redox reactions oxidation reduction redox reaction

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. $4Ag+8CN^{-}+O _{2}+2H _{2}O\rightarrow 4[Ag(CN) _{2}]^{-}+4OH^{-}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In option B, CaO + SiO2 -> CaSiO3, the oxidation states of Ca (+2), O (-2), and Si (+4) remain unchanged. This is an acid-base reaction, not a redox reaction.