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An elastic collision is an encounter between two bodies in which the total kinetic energy of the two bodies remains the same.

Citric acid has 3 carboxyl groups, therefore, when reacts with NaOH, there is a simple salification reaction that will produce the trisodium citrate / sodium citrate. Trisodium citrate is a tribasic salt of citric acid. It is produced by complete neutralization of citric acid with high purity sodium hydroxide or carbonate and subsequent crystallization and dehydration.

krypton and xenon for high-speed pictures in a photographer's flash tube

efflorescence, spontaneous loss of water by a hydrated salt, e.g Sodium trioxocarbonate (IV) decahydrate \(Na_2CO_3. 10H_2O)\) also known as washing soda

The electrolyte is dilute sulfuric acid (= acidified water) which, during electrolysis is split into hydrogen and oxygen gases.

Electrolysis is used extensively in metallurgical processes, such as in extraction (electrowinning) or purification (electrorefining) of metals from ores or compounds and in deposition of metals from solution (electroplating). Copper is purified by electrolysis . Electricity is passed through solutions containing copper compounds, such as copper(II) sulfate.

For a reaction to be feasible, \DeltaG has to be negative.

When two or more gases are mixed together at constant volume, there is an increase in entropy.

The rate of a reaction can be increased by adding a suitable catalyst. A catalyst is a substance which increases the rate of a chemical reaction but it is not used up (remains chemically unchanged at the end). It provides an alternative reaction pathway of lower activation energy.

When amount / volume of gaseous reactants equal amount / volume of gaseous products, the change in pressure has no effect on the equilibrium position.

In flame of pure hydrogen burning in air, the hydrogen (H2) reacts with oxygen (O2) to form water \(H_2O\) with the release of energy. Hydrocarbon combustion refers to the chemical reaction where a hydrocarbon reacts with oxygen to create carbon dioxide, water, and heat. The electrolysis of brine yields chlorine, hydrogen and sodium hydroxide.

The ozone layer in the stratosphere absorbs a portion of the radiation from the sun, preventing it from reaching the planet's surface. Most importantly, it absorbs the portion of UV light called UVB.

When an element exists in more than one crystalline form, those forms are called allotropes; the two most common allotropes of carbon are diamond and graphite. Graphite is used in pencils and lubricants. It is a good conductor of heat and electricity. Its high conductivity makes it useful in electronic products such as electrodes, batteries, and solar panels.

In the presence of heated platinum catalyst, ammonia reacts with excess air to produce nitrogen (II) oxide, NO, (instead of nitrogen) and water.

No expanded working has been attached for this question yet. The verified answer is Option C.