Correct Answer: D. K₂CO₃

Correct Answer: A. Rusting is a reduction process

Correct Answer: B. electron affinity

Correct Answer: A) 2.536

Correct Answer: B) sublimation

Explanation

The options provided are distillation, sublimation, precipitation, and evaporation. Distillation involves separating a mixture of liquids based on differences in boiling points. Precipitation is the formation of a solid from a solution. Evaporation is the conversion of a liquid to a gas.

The correct option in this case is sublimation. Sublimation is the process of conversion of a solid directly to a gas without passing through a liquid phase. This is what occurs when ammonium chloride is heated gently, and it disappears to produce a mixture of two gases. The white cloudy deposit observed on the cooler part of the test tube is a result of the gas condensing back into a solid on the cool surface.

In summary, the process that occurs when solid ammonium chloride is heated gently in a test tube, leading to the production of two gases and a white cloudy deposit on the cooler part of the tube is sublimation.

Correct Answer: D) SP

Correct Answer: C) an alkene

Explanation

To determine the type of hydrocarbon (C_xH_y) involved in the reaction, we can first balance the equation and find the general formula of the hydrocarbon. The balanced equation is:

\(C_xH_y + 9O_2 \rightarrow 6CO_2 + 6H_2O\)

Now, we can equate the number of carbon and hydrogen atoms on both sides of the equation:

Carbon atoms: 6 = x

Hydrogen atoms: 12 = y

So, the hydrocarbon has the formula C₆H₁₂. Now, let's consider the types of hydrocarbons given in the options:

Option A: Alkane - Alkanes have the general formula C_nH_2n+2. In this case, C₆H₁₂ does not fit the formula for an alkane.

Option B: Benzene - Benzene has the formula C₆H₆, which is not the same as the given hydrocarbon.

Option C: Alkene (Correct) - Alkenes have the general formula C_nH_2n. C₆H₁₂ fits this formula, so the hydrocarbon is most likely an alkene.

Option D: Alkyne - Alkynes have the general formula C_nH_2n-2. C₆H₁₂ does not fit the formula for an alkyne.

In conclusion, the hydrocarbon in the reaction is most likely an alkene, which is consistent with the correct option (C).

Correct Answer: D) heating of ammonium chloride

Explanation

Option A, burning of bush, is an example of a chemical change because it involves a chemical reaction that changes the composition of the material being burned. Option B, rusting of a metal, is also a chemical change because it involves the reaction of metal with oxygen in the air to form a new compound.

Option C, dissolution of calcium in water, is a physical change because it involves the breaking of bonds between calcium ions and the anions they were originally bonded to. The calcium ions remain the same, they are just separated from their original compounds and dispersed in the water.

Option D, heating of ammonium chloride, is a physical change because it involves the application of heat to ammonium chloride, causing it to change from a solid to a gas without changing its chemical composition. This change is reversible, as if the gas is cooled it will return to its solid state.

Therefore, the correct answer to this question is option D, heating of ammonium chloride. This is because it is an example of a physical change, which does not change the chemical composition of the substance.

Correct Answer: D. isomeric

Correct Answer: B. cracking