This question is describing the following chemical reaction at equilibrium:

And provides the relative amounts of both A and B at 25 °C and 75 °C, this means the equilibrium expressions and equilibrium constants can be written as:

Thus, by recalling the Van't Hoff's equation, we can write:

Hence, we solve for the enthalpy change as follows:

Finally, we plug in the numbers to obtain:
![\Delta H=\frac{-8.314\frac{J}{mol*K} *ln(0.25/9)}{[\frac{1}{(75+273.15)K} -\frac{1}{(25+273.15)K} ] } \\\\\\\Delta H=4,785.1\frac{J}{mol}](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Cfrac%7B-8.314%5Cfrac%7BJ%7D%7Bmol%2AK%7D%20%2Aln%280.25%2F9%29%7D%7B%5B%5Cfrac%7B1%7D%7B%2875%2B273.15%29K%7D%20-%5Cfrac%7B1%7D%7B%2825%2B273.15%29K%7D%20%5D%20%7D%20%5C%5C%5C%5C%5C%5C%5CDelta%20H%3D4%2C785.1%5Cfrac%7BJ%7D%7Bmol%7D)
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Answer:
The correct answer is option C.
Explanation:

On increasing the pH of the blood the hydronium ions concentration will decrease which will result in decrease in concentration of hydronium ions at the equilibrium state of hydrogen carbonate.
Le-Chatelier's principle:
This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.
According to Le-Chatelier's principle , on decrease in a concentration of the product the equilibrium moves in forward correction to re-establish itself.
So, on increasing the pH, the hydronium ions concentration will decrease which results in disassociation of more hydrogen carbonate to maintain the pH of the blood.
Hence, the correct answer is option C.
You can view more details on each measurement unit: molecular weight of Aluminium or grams The molecular formula for Aluminium is Al. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Aluminium, or 26.981538 grams.