Question

To use Gay-Lussac’s law, which of the following needs to remain constant?
A. Volume and number of moles of a gas
B. Pressure and temperature
C. Temperature and the number of moles of a gas
D. Pressure and the number of moles of a gas
E. Temperature and volume

Answer 1

Hint: To answer the question, Gay-Lussac’s law must be known. Gay-Lussac’s law states that the pressure of a gas is directly proportional to the absolute temperature provided mass and volume of the gas is constant. Also, at constant volume, the pressure of the gas increases with an increase in temperature and decreases with a decrease in temperature. Examples of Gay-Lussac’s law in daily life are pressure cooker, bursting of a tyre, aerosol spray, fire extinguisher, water heater and bullets.

Complete step by step solution:
According to the law When gases react, they do so in volumes that bear a whole number ratio to one another and the volumes of the products, if gaseous, provided the temperature and pressure of the reacting gases and their products remain constant. The pressure of the gas reduces constantly as it is cooled until the gas eventually undergoes condensation and becomes a liquid. It can be expressed as:
$ \Rightarrow $\[P \propto T\]
Where, $P$ is the pressure exerted by the gas , $T$ is the absolute temperature of the gas

Thus, the correct option is A. Volume and number of moles of a gas.

Note: Gay-Lussac primarily investigated the relationship between volume and temperature and published it in 1802, but his work did cover some comparison between pressure and temperature. Gay-Lussac’s (Amontons’) law, Charles’s law, Boyle’s law form the combined gas law. These three gas laws in combination with Avogadro’s law can be generalized by the ideal gas law. Given the relative technology, Amontons was only able to work with air as a gas, where Gay-Lussac was able to experiment with multiple types of common gases, such as oxygen, nitrogen, and hydrogen.