a. Hydrogen
Hydrogen has a line at 410 nm.
Mercury has a line at 405 nm.
Sodium and neon have no lines near 412 nm.
The pressure of the carbon dioxide will be 0.09079 atm.
<h3>What is partial pressure?</h3>
The pressure exerted by the individual gas is known as partial pressure.
The partial pressure is given as

In a mixture of carbon dioxide and oxygen, 40.0% of the gas pressure is exerted by oxygen.
If the total pressure is 115 mmHg.
The total pressure in atm will be
P = 115 mmHg
P = 0.15132 atm
We have

Then the pressure of the carbon dioxide will be 0.09079 atm.
More about the partial pressure link is given below.
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The units of ppm means parts per million. Also, It is equivalent to milligrams per liter. It is one way of expressing concentration of a substance. It u<span>sually used to describe the concentration of something in water or soil. We calculate the mass of CaCO3 as follows:
Mass = 75 mg/L (.050 L) = <span>3.75 mg CaCO3</span></span>