Molarity = mol/liter
0.708M = 0.098mol/L
Rearrange to find L:
0.098mol/0.708M = .138L
For every liter there is 1000 mL:
.138L • 1000mL =138mL KOH
When looking to power your equipment or vehicle with natural gas, the first question that springs to mind is: what is natural gas? A lot of people use natural gas in their homes for cooking and heating, but they don’t really give it some thought. So, let’s see what natural gas is and how it’s different from other forms of fossil fuels like oil and coal.
Natural Gas is a fossil fuel that exist in a gaseous state and is composed mainly of methane (CH4) a small percentage of other hydrocarbons (e.g. ethane). The use of natural gas is becoming more and more popular as it can be used with commercial, industrial, electric power generation and residential applications.
You start by diving each quantity given by the atomic wight of each element:
Phosphorus (P) 
Hydrogen (H) 
Then you divide by the lowest number:
for phosphorus
for hydrogen
So the empirical formula will be:
Answer:
a. 2,9x10⁻⁴ M HCl
Explanation:
A solution is considered acidic when its concentration of H⁺ is higher than 1x10⁻⁷. The higher concentration of H⁺ will be the most acidic solution.
a. 2,9x10⁻⁴ M HCl. In water, this solution dissolves as H⁺ and Cl⁻. That means concentration of H⁺ is 2,9x10⁻⁴ M.
b. 4,5x10⁻⁵M HNO₃. In the same way, concentration of H⁺ is 4,5x10⁻⁵M.
c. 1,0x10⁻⁷M NaCl. As this solution doesn't produce H⁺, the solution is not acidic
d. 1,5x10⁻²M KOH. This solution produce OH⁻. That means the solution is basic nor acidic.
Thus, the solution considered the most acidic is a. 2,9x10⁻⁴ M HCl, because has the higher concentration of H⁺.
I hope it helps!
