Correct Answer: B. carbon (II) oxide and hydrogen

Correct Answer: D) 0.275atm

Explanation

Correct Answer: A) 4

Explanation

In order to understand the question, you need to know what a straight-chain dichloroalkane is. A straight-chain dichloroalkane is an alkane with two chlorine atoms replacing two hydrogen atoms on a linear carbon chain. The formula given is \(C_4H_8Cl_2\), which means the compound has 4 carbon atoms, 8 hydrogen atoms, and 2 chlorine atoms.

To find the number of different straight-chain dichloroalkanes, we need to identify the different positions the two chlorine atoms can be placed on the 4-carbon chain without repeating any arrangement.

Let's use numbers to represent the carbon atoms in the chain (1, 2, 3, and 4) and X to represent the positions of the chlorine atoms. We can have the following combinations:

1. 1,2 (XX00)
2. 1,3 (X0X0)
3. 1,4 (X00X)
4. 2,3 (0XX0)
5. 2,4 (0X0X)
6. 3,4 (00XX)

However, we need to consider that the chain can be flipped, and some of these combinations are identical when the chain is reversed. For example, combination 1 (XX00) is the same as combination 6 (00XX) when flipped. Similarly, combination 3 (X00X) is the same as itself when flipped. So, we only have 4 unique straight-chain dichloroalkanes:

1. 1,2 (XX00)
2. 1,3 (X0X0)
3. 1,4 (X00X)
4. 2,3 (0XX0)

Thus, the correct answer isOption A: 4.

Correct Answer: D) degeneracy of orbitals

Correct Answer: C) i only

Explanation

To determine which of these compounds will dissolve in water to give an alkaline solution, we need to understand the properties of each compound and how they behave when they dissolve in water.

i. \(NaHCO_3\)

Sodium bicarbonate, also known as baking soda, is a weak base. When it dissolves in water, it forms a basic solution. The reaction can be represented as follows:

\(NaHCO_3 + H_2O \rightarrow Na^+ + OH^- + H_2CO_3\)

The presence of hydroxide ions (\(OH^-\) in the solution indicates that it is alkaline in nature.

ii. \(NaHSO_4\)

Sodium hydrogen sulfate, also known as sodium bisulfate, is an acidic salt. When it dissolves in water, it forms an acidic solution. The reaction can be represented as follows:

\(NaHSO_4 + H_2O \rightarrow Na^+ + H_3O^+ + HSO_4^-\)

The presence of hydronium ions (\(H_3O^+\) in the solution indicates that it is acidic in nature.

iii. \(NaCl\)

Sodium chloride, also known as table salt, is a neutral salt. When it dissolves in water, it forms a neutral solution. The reaction can be represented as follows:

\(NaCl \rightarrow Na^+ + Cl^-\)

There are no hydroxide ions (\(OH^-\) or hydronium ions (\(H_3O^+\) formed in this reaction, indicating that the solution is neither acidic nor alkaline.

Therefore, the correct answer isOption C: i only, as only sodium bicarbonate (\(NaHCO_3\) dissolves in water to give an alkaline solution.

Correct Answer: A. 0.5 mol dm_-3 of hydrochloric acid

Correct Answer: A. reaction vessel feels cool during the reaction

Correct Answer: D. Electropositivity of metals decreases down the series

Correct Answer: A) 8140g

Explanation

First, let's find the number of moles of CH\(_4\) produced in the reaction. We can do this by using Avogadro's Number, which tells us the number of particles (atoms, molecules, ions, etc.) in one mole of a substance.

To find the number of moles of CH\(_4\), divide the given number of molecules by Avogadro's Number:

Now, we can use the stoichiometry of the balanced chemical equation to find the number of moles of CO required. As per the equation, 2 moles of CO are required to produce 1 mole of CH\(_4\):

Next, we will find the molar mass of CO:

Finally, we can calculate the mass of CO required by multiplying the number of moles of CO by its molar mass:

So, the mass of CO required to produce 8.75 \(\times\) 10\(^{25}\) molecules of CH\(_4\) is8140g, which isOption A.

Correct Answer: D) lowering the energy barrier of the reaction