Understanding Compressed Gases in Daily Life
The question asks us to identify which substances among the given options are stored and used as compressed gases in our everyday activities. A compressed gas is a gas that is put under pressure, reducing its volume. This is often done to store more gas in a smaller space or to make it easier to transport and use.
Analyzing Each Option
Let's examine each item mentioned:
- (i) LPG for cooking: LPG stands for Liquefied Petroleum Gas. It's a mixture of propane and butane. LPG is stored in cylinders under pressure, which liquefies the gas. When the valve is opened, the pressure decreases, and the liquid turns back into a gas, which is then used for cooking. Therefore, LPG is a compressed gas commonly used in households.
- (ii) Oxygen in hospitals: Medical-grade oxygen is essential for patients who need respiratory support. It is stored in metal cylinders under very high pressure. This allows a significant amount of oxygen gas to be stored in a portable container. Thus, oxygen in hospitals is supplied as a compressed gas.
- (iii) CNG in vehicles: CNG stands for Compressed Natural Gas. It consists mainly of methane and is stored in special high-pressure tanks in vehicles. Burning CNG produces less pollution compared to traditional fuels, making it a popular alternative. It is a prime example of a compressed gas used in daily transportation.
- (iv) Water in bottles: Water (H2O) is a liquid under normal conditions and is stored in bottles as a liquid. While water can turn into steam (a gas) when heated, it is not typically stored or used as a compressed gas in its liquid form in bottles for daily use.
Conclusion on Compressed Gases
Based on the analysis:
- LPG (i) is a compressed gas used for cooking.
- Oxygen (ii) is a compressed gas used in medical settings.
- CNG (iii) is a compressed gas used as fuel for vehicles.
- Water (iv) is a liquid, not a compressed gas in this context.
Therefore, the items that are compressed gases commonly used in daily life are LPG for cooking, Oxygen in hospitals, and CNG in vehicles.
The combination that correctly includes these three is (i), (ii), and (iii) only.
Important Questions from Chemistry
Select the option that is true regarding the following two statements labelled Assertion (A) and Reason (R).
Assertion (A): Copper wire in iron sulphate solution shows no visible reaction.
Reason (R): Copper is less reactive than iron.Which of the following statements are correct?
(i) Solid $CO_2$ is called dry ice.
(ii) Solid $CO_2$ changes directly into gas at 1 atm pressure.
(iii) Pressure and temperature can change the state of matter.
(iv) Solid $CO_2$ melts into liquid $CO_2$ before becoming gas.- Identify the correct match between the compound and type of carbon-carbon bond.
Compound C-C bond type (i) Ethane (a) Double bond (ii) Ethene (b) Single bond (iii) Ethyne (c) Triple bond - The rate of evaporation increases with:
i. an increase in surface area
ii. an increase in temperature
iii. a decrease in humidity - Select the option that is true regarding the following two statements labelled Assertion (A) and Reason (R).
Assertion (A): In electrolytic refining, insoluble impurities settle down at the bottom of the anode.
Reason(R): These impurities do not dissolve in the electrolyte.
