Correct Answer: C) dissolves when it absorbs moistures

Explanation

Hygroscopicity is a property of substances that enables them to absorb moisture from the air. This means that if a substance is hygroscopic, it can absorb water vapour from the atmosphere. The question is asking us to identify what it means for a substance to be hygroscopic. From the options given, option C is correct. A substance is said to be hygroscopic if it dissolves when it absorbs moisture.

Hygroscopic substances are commonly used as drying agents or desiccants due to their ability to absorb moisture. Examples of hygroscopic substances include calcium chloride, silica gel, and concentrated sulfuric acid. When these substances are exposed to air, they can absorb moisture and become wet. This property is useful in many different industrial and scientific applications, including the manufacture of pharmaceuticals and the storage of electronic components.

Option A, which states that a substance that is hygroscopic does not absorb moisture, is incorrect. Option B, which states that a substance that is hygroscopic is suspended in water, is also incorrect. Option D, which states that a substance that is hygroscopic hydrolyzes in water, is incorrect as well.

In summary, a substance is said to be hygroscopic if it dissolves when it absorbs moisture. This property is useful in many different applications and is exhibited by certain substances such as calcium chloride, silica gel, and concentrated sulfuric acid.

Explanation

(a) 1s\(^2\)2s\(^2\)2p\(^6\)3s\(^2\)3p\(^3\)

(b) Cu\(^2\) + 4NH\(_3\) —> Cu(NH\(_3)^{2+}_4\)

(Deep blue in colour)

Correct Answer: A) ethene

Correct Answer: B. Using aerobic bacteria

Correct Answer: D) precipitate

Correct Answer: B) 25

Explanation

Let's represent the relative abundance of the isotope with mass number 35 as x and the relative abundance of the isotope with mass number 37 as y. Since the sum of the relative abundances should be equal to 100%, we can write the equation:

x + y = 100

We know that the atomic mass of chlorine (35.5) is the weighted average of the isotopes. We can write this as:

(35 * x + 37 * y) / 100 = 35.5

Now we need to solve the system of equations to find the value of y, which is the relative abundance of the isotope of mass number 37.

x + y = 100

35x + 37y = 3550

Substitute x = 100 - y into the second equation:

35(100 - y) + 37y = 3550

3500 - 35y + 37y = 3550

2y = 50

Now divide by 2:

y = 25

Therefore, the relative abundance of the isotope of mass number 37 is 25 (Option B).

Correct Answer: D) 1.0

Explanation

First, let's understand diffusion. Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration, eventually leading to equal concentrations throughout the space. In gases, diffusion is mainly influenced by the molecular weight or molar mass of the gas.

In this question, we are given the rate of diffusion of oxygen gas as 1 and asked to find the rate of diffusion of methane, whose relative molar mass is 16. To solve this, we will use Graham's law of diffusion, which states:

\[\frac{Rate_1}{Rate_2} = \sqrt{\frac{Molar\,mass_2}{Molar\,mass_1}}\]

Where Rate_1 and Rate_2 are the rates of diffusion of gas 1 and gas 2, and Molar mass_1 and Molar mass_2 are the molar masses of gas 1 and gas 2, respectively.

First, let's find the molar mass of oxygen gas. Oxygen has a molar mass of 16 g/mol, and since oxygen gas is diatomic (O₂), its molar mass is 2 * 16 = 32 g/mol. Now we can apply Graham's law to find the rate of diffusion of methane (CH₄):

Plugging in the given values:

Now, we can solve for the rate of diffusion of methane:

After simplifying, we find that the rate of diffusion of methane is equal to 1.0, which is the correct answer (Option D).

In summary, the rate of diffusion of methane is the same as the rate of diffusion of oxygen gas, which is 1.0, according to Graham's law of diffusion.

Correct Answer: B. nearness to raw materials

Correct Answer: B. RCHO

Correct Answer: D) cellulose

Explanation

The question is asking about the composition of cotton. Cotton is a natural fiber that is widely used in the textile industry for making clothes, bed sheets, and other household items. The question is asking which substance is almost pure in cotton.

From the options given, the correct answer is option D: cellulose. Cellulose is a complex carbohydrate that is found in the cell walls of plants. It is the main component of cotton fiber and accounts for about 90% of its weight. Cellulose is made up of long chains of glucose molecules that are linked together by chemical bonds.

Starch, option A, is another complex carbohydrate found in plants, but it is not the main component of cotton fiber. Protein, option B, is a macromolecule composed of amino acids and is not found in cotton fiber. Animal fiber, option C, refers to fibers obtained from animal sources such as wool, silk, and fur, and is not related to cotton fiber.

Understanding the composition of cotton is important in various industries such as textiles, fashion, and agriculture. Knowledge of cellulose and its properties is also important in fields such as biochemistry and material science.