Chemical Reactions And Equations

The electrolytic decomposition of water produces hydrogen gas and oxygen gas in a 2:1 ratio by volume. This means that for every 2 volumes of hydrogen gas produced, 1 volume of oxygen gas is produced. This ratio is a result of the balanced chemical equation for the electrolysis of water, which shows that 2 moles of water molecules break down to form 2 moles of hydrogen gas and 1 mole of oxygen gas. Since gases occupy the same volume under the same conditions of temperature and pressure, the volume ratio of the two gases is 2:1.

Calcium oxide (CaO) reacts with water (H2O) to form calcium hydroxide (Ca(OH)2), also known as slaked lime. This reaction is exothermic and produces a white, powdery substance. Slaked lime is commonly used in construction, agriculture, and chemical industries for various purposes such as soil stabilization, water treatment, and manufacturing of cement and mortar. It is not carbon dioxide, calcium oxide, or oxygen gas as these are not the products of the reaction between calcium oxide and water.

Thermal decomposition refers to a reaction in which a compound breaks down into simpler substances due to the application of heat. In this type of reaction, the compound undergoes a chemical change as a result of the heat energy absorbed, leading to the formation of new products. Therefore, the given reaction is an example of thermal decomposition as it involves the breakdown of a compound through the application of heat.

When sulphuric acid reacts with barium chloride solution, it forms a white precipitate of barium sulphate. This is because sulphuric acid reacts with barium chloride to produce barium sulphate, which is insoluble in water and appears as a white solid. The other options, hydrochloric acid, chlorine, and sulphur, are not formed as precipitates in this reaction.

Rancidity refers to the spoilage of food due to the oxidation of fats or oils present in it. When fats or oils are exposed to oxygen, they undergo a chemical reaction called oxidation, resulting in the development of unpleasant flavors and odors. This process is known as rancidity. Therefore, the correct answer is "Oxidation of oil present in food."

When carbon dioxide is passed in lime water, it reacts with the calcium hydroxide present in lime water to form calcium carbonate. This reaction results in the formation of a white precipitate, which causes the lime water to turn milky. Calcium carbonate is insoluble in water, hence it appears as a solid precipitate, giving the milky appearance to the lime water.

When Copper metal is dipped in the solution of zinc sulphate, no reaction takes place. This is because copper is less reactive than zinc in the reactivity series. Therefore, copper does not displace zinc from its compound (zinc sulphate) to form a new compound. Hence, there is no chemical change or reaction observed in this scenario.

A chemical reaction does not involve changing the atoms of one element into those of another element to form new products. Chemical reactions involve the rearrangement of atoms and the breaking and formation of chemical bonds, but they do not result in a change in the identity of the elements involved.

The correct chemical formula for lead sulphate is PbSO4, not Pb(SO4)2. The number 2 after the parenthesis indicates that there are two sulfate ions, which is incorrect. The correct formula should have only one sulfate ion, represented by the SO4 group.

When lead nitrate is decomposed, nitrogen dioxide gas is evolved. Nitrogen dioxide gas is known to be brown in color.