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Multiple choice chemistry oxidation- reduction reactions redox reactions and electrode processes redox and electrode processes applications of redox reaction

The passage of electricity in the Daniell cell when $Zn$ and $Cu$ electrodes are connected is from:

  1. $Cu$ to $Zn$ in the cell
  2. $Cu$ to $Zn$ outside the cell
  3. $Zn$ to $Cu$ outside the cell
  4. $Zn$ to $Cu$ in the cell
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Daniell cell, Zn acts an anode and Cu acts as cathode, electron flow takes place from anode to cathode and hence, electricity flows from Cu to Zn outside the cell.

Multiple choice chemistry oxidation- reduction reactions redox reactions and electrode processes redox and electrode processes applications of redox reaction

Daniel cell operates under nonstandard state conditions. If the equation of the cell reaction is multiplied by 2 then:

  1. $E$ and $E^o$ remain unchanged
  2. $E$ is doubled
  3. $n$ remains unchanged in Nernst equation
  4. $Q$ is halved in Nernst equation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nernst's equation states ${ E } _{ cell }={ E } _{ cell }^{ 0 }+\dfrac { RT }{ nF } ln\left[ { M }^{ + } \right] $

Where $E$ and ${ E }^{ 0 }$ of cell are independent of volume/quantity of reacting species in electrolyte, they are intunsic properties of cell. Hence, on doubling cell equation of Daniel cell.
$Zn\left| { Zn }^{ 2+ } \right| \left| { Cu }^{ 2+ } \right| Cu$,
its e.m.f $(E)$ and standard e.m.f $\left( { E }^{ 0 } \right) $ remain unchanged where ${ E }^{ 0 }$ stays at $1.09V$.

Multiple choice chemistry oxidation- reduction reactions redox reactions and electrode processes redox and electrode processes applications of redox reaction

For the Daniel cell involving the cell reaction${ Zn } _{ (s) }+{ { Cu }^{ +2 } } _{ (aq) }\rightleftharpoons { { { Zn }^{ +2 } } } _{ (aq) }+{ Cu } _{ (s) }$ the standard free energies of formation of  ${ Zn } _{ (s) }$, ${ Cu } _{ (s) }$, ${ { Cu }^{ +2 } } _{ (aq) }$ and ${ { { Zn }^{ +2 } } } _{ (aq) }$ are 0, 0, 64.4 KJ/Mole and -154.0 KJ/Mole, respectively. Calculate the standard EMF of the cell?

  1. $2.13 Volts$
  2. $1.13 Volts$
  3. $2.26 Volts$
  4. $3.42 Volts$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\because \quad \Delta { G }^{ 0 }=\left( { G } _{ { Zn }^{ 2+ } }^{ 0 }-{ G } _{ { Cu }^{ 2+ } }^{ 0 } \right) $ $= (-154-64.4) KJ/Mole$

$\therefore(-2\times{E}^{0}\times F)$ $=(-218.4\times {10}^3)$
$\therefore E^0=1.1316\quad volt$

Multiple choice chemistry oxidation- reduction reactions redox reactions and electrode processes redox and electrode processes applications of redox reaction

Which of the following statement is TRUE for the electrochemical Daniel cell :

  1. Electron flow from Zinc electrode to Copper electrode.

  2. Current flows from zinc electrode to copper electrode.

  3. Cation moves towards copper electrode.

  4. Cation moves towards zinc electrode.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During reaction of $Zn\rightarrow{Zn}^{2+}+{2e}^{-}$ extra electron goes from anode to cathode or flow of $e^-$ from Zinc to Copper takes place and current flows from Copper to Zinc.

Multiple choice biochemical polymers polymerisation chemistry

Nucleic acids are the polymers of __________

  1. nucleosides

  2. nucleotides

  3. bases

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

Nucleic acids are made up of individual monomers called nucleotides

Multiple choice biochemical polymers polymerisation chemistry

Which of the following is correxect bonding in nucleotide?

  1. $A - T, \ G - C$
  2. $A - G,\ T - C$
  3. $G - T,\ A - C$
  4. $A - A,\ T - T$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct bonding pairs in Nucleotide are Adenine- Thymine, Guanine- Cytosine where Adenine, Thymine, Guanine, Cytosine are bases which form in pairs to build up Nucleotides.

Multiple choice biochemical polymers polymerisation chemistry

A unit in nucleic acid which contains 'base-sugar phosphate' unit is called ?

  1. nuleotide

  2. nucleoside

  3. phosphotide

  4. polypeptide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Nucleotides are composed of three sub-unit molecules: a nitrogenous base, a five-carbon sugar (ribose or deoxyribose), and at least one phosphate group.
Multiple choice biochemical polymers polymerisation chemistry

Which of the following bases is not present in DNA?

  1. Adenine

  2. Thymine

  3. Cytosine

  4. Uracil
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
In DNA, four bases have been found. They are adenine (A), guanine (G), cytosine (C) and thymine (T).
Uracil is present in RNA.
Multiple choice biochemical polymers polymerisation chemistry

The $AT/GC$ ratio in human beings is: (where $A=$adenine,$T=$thymine,$G=$Guanine,$C=$cytosine)

  1. $1$
  2. $1.52$
  3. $9.3$
  4. $2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A-T/G-C ratio is human beings is equal to 1.52

where A=Adenine T-Thymine, G-Guanine, C-Cytosine

Multiple choice biochemical polymers polymerisation chemistry

RNA is ?

  1. single helix strand

  2. double helix strand

  3. right hand twisted double helix strand

  4. triple helix strand
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
RNA is a single-stranded molecule in many of its biological roles and consists of a much shorter chain of nucleotides.