Answer: A.
B.
C.
Thus solution B is basic in nature.
Explanation:
pH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration.
pH for acidic solutions is less than 7, for basic solutions it is more than 7 and for neutral solutions it is equal to 7.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
![pOH=-log[OH^-]](https://tex.z-dn.net/?f=pOH%3D-log%5BOH%5E-%5D)

or ![[H^+][OH^-]=10^{-14}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%5BOH%5E-%5D%3D10%5E%7B-14%7D)
A.
![pH=-log[H_3O^+]=-log[0.64\times 10^{-7}]=7](https://tex.z-dn.net/?f=pH%3D-log%5BH_3O%5E%2B%5D%3D-log%5B0.64%5Ctimes%2010%5E%7B-7%7D%5D%3D7)
B.
![pH=-log[H_3O^+]=-log[9.43\times 10^{-9}]=8](https://tex.z-dn.net/?f=pH%3D-log%5BH_3O%5E%2B%5D%3D-log%5B9.43%5Ctimes%2010%5E%7B-9%7D%5D%3D8)
C.
![pH=-log[H_3O^+]=-log[0.000775]=3](https://tex.z-dn.net/?f=pH%3D-log%5BH_3O%5E%2B%5D%3D-log%5B0.000775%5D%3D3)
Thus solution B is basic.
<span>The melting of ice is an event which is endothermic. Endothermic is the process when heat is transfer from the environment to the object. It happens when the onject absorbs the heat just like melting of ice. The ice is in solid form due to the compaction of positively charged atoms in it but when heat carrying electrons made contact to it, it melted.</span>
To find moles : moles= Mass (C₄H₂O₄) / RFM (C₄H₂O₄)
so moles = 147.7 / 114 = <span>1.2956mol
hope that helps </span>
B. A los to cover a coffee mug