SSC CGL Chemistry Questions Solved Problems with Detailed Solutions [Free PDF]

One mole of an ideal gas occupies a volume of ______ litre at 273 K and 1 atm pressure.

Answer (Detailed Solution Below)

SSC CGL Chemistry Questions Question 1 Detailed Solution

The correct answer is 22.4 Litre.

Key Points

• At standard temperature and pressure (STP) one mole of any gas occupies a volume of 22.4 L.
• The standard temperature is 0°C (273.15 K) and the standard pressure is 1 atm.

Important Points

Avogadro’s hypothesis states that:

• Equal volumes of any gas at the same temperature and pressure contain the same number of particles.

The ideal gas equation is:

• PV = nRT
• n=Number of moles
• R=The gas constant.
• The SI value for R is 8.31441 J K-1 mol-1.

SSC CGL Chemistry Questions Question 2:

Why is water fluoridation, which is the controlled adjustment of fluoride to public water supply, done?

1. To prevent eye disease
2. To prevent vitamin deficiency
3. To prevent tooth decay
4. To prevent bone disease

Answer (Detailed Solution Below)

SSC CGL Chemistry Questions Question 2 Detailed Solution

The correct answer is To prevent tooth decay.

Key Points

• Water fluoridation is the addition of fluoride to a public water supply with the express purpose of preventing tooth decay.
• Fluoridated water contains a sufficient amount of fluoride to prevent cavities; this can occur naturally or through the addition of fluoride.
• Fluoridated water works on dental surfaces by producing low levels of fluoride in saliva, which slows the demineralization of tooth enamel and speeds up the remineralization of tooth enamel in the early stages of cavities.
• In most industrialised countries, tooth decay is still a serious public health concern, impacting 60–90 percent of kids and the vast majority of adults.
• Fluoridation of drinking water decreases cavities in children, but its effectiveness in adults is unclear.​

Additional Information

• Damage to a tooth's surface, or enamel, is known as tooth decay.
• It occurs when oral bacteria produce acids that destroy the enamel.
• Cavities (dental caries) are holes in your teeth caused by tooth decay.
• If left untreated, dental decay can lead to discomfort, infection, and even tooth loss.