Answer: Option (4) is the correct answer.
Explanation:
Activation energy is the minimum amount of energy required by the reactants to participate in the chemical reaction.
Therefore, reactant molecules whose energy is less than the activation energy are not able to participate in the reaction. Hence, a catalyst lowers the activation energy so that molecules with less energy can also participate in the reaction.
Thus, a catalyst is a specie that increases the reaction rate and has a lower activation energy.
Affects populations,
Occurs when there is genetic variation
Selects organisms with certain traits to survive.
Answer:
pKa of the histidine = 9.67
Explanation:
The relation between standard Gibbs energy and equilibrium constant is shown below as:
![\Delta{G^0} =-RT \ln \frac{[His]}{[His+]}](https://tex.z-dn.net/?f=%5CDelta%7BG%5E0%7D%20%3D-RT%20%5Cln%20%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D)
R is Gas constant having value = 0.008314 kJ / K mol
Given temperature, T = 293 K
Given, 
So, Applying in the equation as:-
![15\ kJ/mol=-0.008314\ kJ/Kmol\times 293\ K\times \ln \frac{[His]}{[His+]}](https://tex.z-dn.net/?f=15%5C%20kJ%2Fmol%3D-0.008314%5C%20kJ%2FKmol%5Ctimes%20293%5C%20K%5Ctimes%20%5Cln%20%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D)
Thus,
![\frac{[His]}{[His+]}=e^{\frac{15}{-0.008314\times 293}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D%3De%5E%7B%5Cfrac%7B15%7D%7B-0.008314%5Ctimes%20293%7D)
![\frac{[His]}{[His+]}=0.00211](https://tex.z-dn.net/?f=%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D%3D0.00211)
Also, considering:-
![pH=pKa+log\frac{[His]}{[His+]}](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%5Cfrac%7B%5BHis%5D%7D%7B%5BHis%2B%5D%7D)
Given that:- pH = 7.0
So, 
<u>pKa of the histidine = 9.67</u>
Oxidation reaction
In ---> In³⁺ + 3e ---1)
reduction reaction
Cd²⁺ + 2e ---> Cd ---2)
when balancing the reactions, electrons have to be balanced. to balance the electrons multiple 1st reaction by 2 and 2nd reaction by 3
1) x 2
2) x 3
2In ---> 2In³⁺ + 6e
3Cd²⁺ + 6e ---> 3Cd
add the 2 equations to obtain the overall reaction
2In + 3Cd²⁺ ---> 2In³⁺ + 3Cd
Answer:
the difference in electronegativity is so large (2.04) that the bonding electrons spend almost all their time on the nitrogen atom.
Explanation:
Because calcium loses 2 electrons to become Ca2+, and nitrogen gains 3 electrons to become N3−, you need two calcium atoms and three nitrogen atoms in order to form a neutral compound.
