Answer: -
2.5 mL
Explanation: -
Volume of final solution = 10 mL
Strength of final solution = 10 mg / mL
Amount of drug required = Volume of final solution x strength of final solution
= 10 mL x 10 mg/ mL
= 100 mg.
Strength of supplied drug = 40mg/ mL
Volume of supplied drug required = 
= 2.5 mL
Thus to make 10 ml of a 10 mg/ml solution. 2.5 mL will be needed.
<u>Answer:</u>
<em>A. 10.25</em>
<em></em>
<u>Explanation:</u>
Pkb =4.77
So pka = 14 - pka = 9.23


Initial 0.50M 0 0
Change -x +x +x
Equilibrium 0.50M-x +x +x


(-x is neglected) so we get

![pH=-log[H^3 O^+]\\\\pH=-log[1.72\times10^{-5}]\\\\pH=4.76](https://tex.z-dn.net/?f=pH%3D-log%5BH%5E3%20O%5E%2B%5D%5C%5C%5C%5CpH%3D-log%5B1.72%5Ctimes10%5E%7B-5%7D%5D%5C%5C%5C%5CpH%3D4.76)
pOH = 14 - pH
= 14 - 4.76
pOH = 9.24 is the answer
Option A - 10.25 is the answer which is close to 9.24
When the temperature increases the molecules of the liquid gain energy and kinetic energy increases, so it makes a pressure above the liquid