Answer :
The concentration of 
before any titrant added to our starting material is 0.200 M.
The pH based on this ion concentration is 0.698
Explanation :
First we have to calculate the concentration of before any titrant is added to our starting material.
As we are given:
Concentration of HBr = 0.200 M
As we know that the HBr is a strong acid that dissociates complete to give hydrogen ion and bromide ion 
.
As, 1 M of HBr dissociates to give 1 M of
So, 0.200 M of HBr dissociates to give 0.200 M of
Thus, the concentration of before any titrant added to our starting material is 0.200 M.
Now we have to calculate the pH based on this ion concentration.
pH : It is defined as the negative logarithm of hydrogen ion concentration.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
Thus, the pH based on this ion concentration is 0.698
2-ethyl-4,4 -dimethyl hex-1-ene.
Answer:-
(iv) (i) + (II)
Explanation:-
Hydrogen bonds Occur between Hydrogen and an element with high electronegativity like N or O.
DNA base pairs are arranged such that they are complimentary. Hence hydrogen bonding will occur between both the amide carbonyl and NH2 as well as the amide NH and Nitrogen of the cyclic C=N-C group.
Answer:
Here is the complete statement: The overall change in enthalpy of a reaction depend ONLY ON REACTANTS AND THE PRODUCTS.
Explanation:
Change in enthalpy of a chemical reaction refers to the heat change that is associated with a chemical change when the pressure is held constant. Generally, chemical reaction involves the breaking of chemical bonds in the reactants and the formation of new chemical bonds in the products. The breaking and forming of bonds involve heat change; the amount of heat that is given off and absorb in each chemical reaction depend on the type of reactants and products that are involved in the chemical reaction.
