Trainers use this substance because the reaction of the product on the skin is an exothermic one. This produces a feeling of warmth and heat. Heating an injury like a sprain with warmth or heat increases blood flow to the area and promotes healing as the flow of blood carries the necessary substances for healing.
Answer : The correct option is, 
Explanation :
Amino acid : The acid that contains two functional groups that are carboxylic group, 
and ammine group, .
When the two or more that two amino acids join together with the help of peptide bond, they produces polypeptide chain or protein.
The bond present between the two amino acid is called a peptide bond.
The peptide bond is a chemical bond that is formed between the two molecules when the nitrogen of one amino acid react with the carbon of another amino acid by releasing a water molecule. This is a dehydration synthesis or condensation reaction.
From this we conclude that, only two functional groups carboxylic group, and ammine group, are present in all amino acids.
Hence, the correct option is,
First, we write the half equations for the reduction of the chemical species present:
Cu⁺² + 2e → Cu; E° = 0.34 V
Ni⁺² + 2e → Ni; E° = - 0.23 V
In order to determine the potential of the cell, we find the difference between the two values. For this:
E(cell) = 0.34 - (-0.23)
E(cell) = 0.57 V
The second option is correct. (The difference in values is due to different values in literature, and it is negligible)
__MgF2 + __Li2CO3 + __ 2LiF
Explanation:
As per Brønsted-Lowry concept of acids and bases, chemical species which donate proton are called Brønsted-Lowry acids.
The chemical species which accept proton are called Brønsted-Lowry base.
(a) 
is Bronsted lowry acid and 
is its conjugate base.
is Bronsted lowry base and 
is its conjugate acid.
(b)
is Bronsted lowry base and HCN is its conjugate acid.
is Bronsted lowry acid and 
is its conjugate base.
(c)
is Bronsted lowry acid and 
is its conjugate base.
Cl^- is Bronsted lowry base and HCl is its conjugate acid.
(d)
is Bronsted lowry acid and 
is its conjugate base.
OH^- is Bronsted lowry base and is its conjugate acid.
(e)
is Bronsted lowry base and OH- is its conjugate acid.
is Bronsted lowry acid and OH- is its conjugate base.
