Question

Vander Waal's equation for a gas is stated as $P=\frac{nRT}{V-nb}-a(\frac{n}{V}{)}^2$.This equation reduce to the perfect gas equation,$P=\frac{nRT}{V}$ when:

• A. temperature is sufficient high and pressure is low
• B. temperature is sufficient high low and pressure is high
• C. both temperature and pressure are very high
• D. both temperature and pressure are very low

Answer 1

The correct option is A temperature is sufficient high and pressure is low

Van der waal equation:

$(p+\frac{a{n}^2}{v^2})(v-nb)=nRT$

or,

$P=\frac{nRT}{v-nb}-a{\left(\frac{n}{v}\right)}^2$

where, v is volume

P is pressure

T is Temperature

n is mole of gas

R is universal gas constant.

the ideal gas equation works well when intermolecular attractions between gas molecular are negligible and the gas molecules themselves do not occupy a significant part of the whole volume. This is usually true when the pressure is low and the temperature is high.

Hence, correct option is $A$