Explanation

For water, the boiling point is 100ºC at a pressure of 1 atm

The boiling point of water decreases at higher altitudes due to Low atmospheric pressure

The boiling point of water increases with increased atmospheric pressure

The boiling point of water decreases with decreased atmospheric pressure

ND17-1-2023

Explanation

Hydrocarbons: These are compounds composed solely of carbon and hydrogen atoms. 

Alcohols: These compounds contain a hydroxyl group (-OH) attached to a carbon atom. 

Carboxylic acids: These compounds contain a carboxyl group (-COOH) attached to a carbon atom.

Essentially, all of these types of compounds involve carbon as a central component in their molecular structure. 

Explanation

After casting, ordinary cement concrete shrinks on drying.

This shrinkage is a natural process where water evaporates from the concrete, causing it to reduce in volume.

The shrinkage happens even without changes in mass or temperature, driven by the loss of capillary water from within the concrete. 

Explanation

In a zero-order reaction, the rate of reaction is independent of the concentration of the reactants and is equal to the rate constant k.

The rate equation for a zero-order reaction is  Rate=k, where the rate of reaction is constant and does not change with varying concentrations of reactants. 

Explanation

Chlorine free radicals from CFCs can destroy thousands of ozone molecules.

UV radiation splits O₂ into O atoms, which form ozone (O₃).

The ozone hole refers to depletion of total ozone in the stratosphere.

Explanation

Out of the 20 standard amino acids, the human body can synthesize 10 non-essential amino acids.

The remaining 10 essential amino acids must be obtained from diet.

Explanation

1 gram of carbohydrate provides about 4 kilocalories of energy.

This is the same as protein (4 kcal/g), while fats give 9 kcal/g.

Explanation

Monosaccharides are the simplest carbohydrates and cannot be hydrolyzed further into smaller sugar units.

Disaccharides and polysaccharides can be hydrolyzed to yield monosaccharides.

Explanation

Fractional crystallization: This method purifies a compound based on differences in solubility.

It involves dissolving the mixture in a solvent at a high temperature and then allowing it to cool gradually.

As the temperature decreases, the less soluble component (the product) crystallizes first, leaving the more soluble impurities behind in the solution.

Explanation

A salt of a weak base and strong acid undergoes hydrolysis in water.

This produces H⁺ ions, making the solution acidic.