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Solid species are not shown in equilibrium constant expressions because their concentrations do not change significantly during a reaction. The activity of pure liquids and solids is 1 and the activity of a solution can be estimated using its concentration. So, pure liquids and solids actually are involved, but since their activities are equal to 1, they don't change the equilibrium constant and so are often left out. The equilibrium constant expression only contains those species whose concentrations could change significantly during the reaction - gaseous and dissolved species. Option D is the correct answer.

Allotropy is the existence of two or more different physical forms of an element. For instance, Carbon exhibit allotropy as it exists in about three different forms, physically such as Diamond, Graphite and amorphous Carbon.

Vulcanization is a process that involves heating rubber with sulphur to improve its strength and elasticity. The process is carried out by mixing latex with sulphur and heating it. Other vulcanizing agents, like selenium and tellurium, are sometimes used, but sulphur is the most common.

The compression ratio of hydrogen is much higher as compared to traditional fuels, which boosts the efficiency and minimizes the carbon emission. Many domestic resources might be utilized to produce hydrogen, which could generate no greenhouse emissions. However, hydrogen gas is not directly a greenhouse gas, even though its chemical reactions change the abundances of the greenhouse gases methane, ozone etc. Option D is the correct answer

The refreshing and characteristic taste of soda water and other soft drinks is as a result of the presence of carbon(IV)oxide. Carbon(iv) oxide does not just act as a preservative in carbonated drinks but also gives the refreshing taste.

The form of carbon used for absorbing poisonous gases and purifying noble gases is activated carbon. Activated carbon is a highly porous form of carbon that has a large surface area, allowing it to adsorb (not absorb) various gases, liquids, or impurities. Thus, Elm wood is a good source of activated carbon. Therefore, wood charcoal is the right answer.

Synthesis gas is a mixture of carbon monoxide (CO) and hydrogen gas (H2).i.e CO + H2. It's also known as water gas because of its use in the synthesis of methanol and other hydrocarbons.

When potassium is heated, it produces a violet or lilac flame because the electrons are excited to higher energy orbitals.

Apart from the fact that Copper is a transition metal while Silver is not, both of them reducing agents, thus they are not easily oxidized. The correct answer is option B.

Hematite is an iron oxide with the chemical formula Fe2O3

The repeating unit in natural rubber is isoprene. Isoprene is a monomer of natural rubber, which is made from latex, a dispersion of isoprene.

Unsaturated organic compounds are identified by the decolorization of bromine water.The acidified potassium manganate(VII) solution oxidizes the alkene by breaking the carbon-carbon double bond and replacing it with two carbon-oxygen double bonds. The products are known as carbonyl compounds because they contain the carbonyl group, C=O. Thus, they are decolourized as well.

The conditions necessary for extracting a water molecule from two ethanol molecules are: Concentrated sulfuric acid: The reaction requires concentrated sulfuric acid. Temperature: The reaction requires a temperature of 140^\circC. Excess ethanol: The reaction requires excess ethanol. The reaction that extracts a water molecule from two ethanol molecules is called dehydration, and it produces diethyl ether and a water molecule. Two ethanol molecules can also be dehydrated to form diethyl ether and a water molecule. This reaction also requires a high temperature, such as 140^\circC, and concentrated sulfuric acid. The correct answer then is excess acid and a higher temperature. - Option C

Tetrachloromethane is an effective solvent within the chemical industry and is used to clean machinery and electrical equipment. It is however used to remove grease in the industries.

When calcium carbide reacts with water, it produces acetylene(also known as ethyne) gas and calcium hydroxide