Q1: Which of the following is a commonly used manometric liquid for low pressure range?

ANS:B - Carbon tetrachloride

Carbon tetrachloride (CCl4) is a colorless, dense liquid that was historically used for various industrial and laboratory applications. It has a tetrahedral molecular geometry, with one carbon atom bonded to four chlorine atoms. Here are some key characteristics and properties of carbon tetrachloride:

1. Chemical Stability: Carbon tetrachloride is relatively chemically stable under normal conditions. It is non-flammable and non-reactive with most common materials. However, it can react with strong reducing agents or in the presence of UV light to produce toxic gases such as phosgene (COCl2).
2. Solvent Properties: Carbon tetrachloride is an excellent solvent for non-polar and moderately polar compounds. It was commonly used as a solvent in organic chemistry laboratories for dissolving and extracting organic compounds. However, its use as a solvent has declined due to its toxicity and environmental concerns.
3. High Density: Carbon tetrachloride has a high density, which makes it useful for certain applications such as liquid density measurements and as a manometric liquid in pressure gauges and barometers.
4. Refractive Index: Carbon tetrachloride has a relatively high refractive index, making it useful in refractometry and optical measurements.
5. Toxicity: Carbon tetrachloride is toxic to humans and animals if ingested, inhaled, or absorbed through the skin. Prolonged exposure to carbon tetrachloride can cause damage to the liver, kidneys, and central nervous system. Due to its toxicity, the use of carbon tetrachloride has been restricted in many countries, and safer alternatives have been developed for most of its former applications.

Overall, while carbon tetrachloride has some useful properties, its toxicity and environmental hazards have led to a significant reduction in its use. Safer alternatives are now preferred for most applications where carbon tetrachloride was once commonly used.