Answer:
219 mmHg
Step-by-step explanation:
The partial pressure of a gas refers to the pressure exerted by one of the gases in a mixture of gases.
The total pressure of a gas is the sum of all the partial pressures of all the gases in the mixture.
Since the total pressure = 745 mmHg
The partial pressure of helium is;
745 - (125 + 214 + 187)
Partial Pressure of helium gas= 219 mmHg