SAT (Stage-1) Mock Test - 48

The atomic radius increases down the group and decreases across the period.

Hence, C has the smallest atomic radius.

Electronegativity decreases down the group and increases across the period.

Hence, C is the most electronegative element.

Corrosion of iron is caused by the reaction of iron with oxygen and moisture. It is an example of oxidation reaction. This leads to the formation of reddish-brown rust on the surface of iron articles.

Rancidity is caused by the oxidation of fats, oils, and lipids present in food materials causing them to smell foul and taste bad.
Galvanisation is used to prevent corrosion, while antioxidants are added to the food materials to avoid rancidity.

Sodium carbonate, Na₂CO₃, is also known as washing soda. It can remove both temporary and permanent hardness from water, which is due to the presence of Ca⁺² and Mg⁺² ions in water, by precipitating them out as carbonates.

Calcium ions + sodium carbonate → Calcium carbonate + sodium ions

Ca²⁺(aq) + Na₂CO₃(aq) → CaCO₃(s) + 2Na⁺(aq)

A reaction of an alcohol with a carboxylic acid in the presence of concentrated sulphuric acid as a catalyst to produce an ester and water is called an esterification reaction.
Esters are organic compounds having a fruity odour.

Ethanoic acid + Ethanol  Ethyl ethanoate + H₂O

2FeCl₃ + SO₂ + 2H₂O → H₂SO₄ + 2HCl + 2FeCl₂

Fe is reduced because it loses one electron and the oxidation state changes from +3 to +2.

Calcium sulphate hemihydrate CaSO₄. 1/2 H₂O, commonly known as plaster of Paris, is used to support fractured bones.

When a paste of this salt is made with water, it sets into a hard mass on drying.

The method of solvent extraction is used for separating the components of a liquid that have different wetting properties in a given solvent.

Mixture of sulphur and sand can be separated by solvent extraction method.

On adding the CS₂ to the mixture, only sulphur dissolves and the sand can be separated out by filtration.

The element with Z = 15 is phosphorous.

The electronic configuration is: 2, 8, 5.

Since there are three occupied shells, it belongs to Period 3.

Since there are five valence electrons, it belongs to Group 15 (10 + 5).

Therefore, the percentage of gold in 22K gold is 91.67%.

On dilution, the concentration of the ions per unit volume of the solution decreases.

In case of acids, the acidic strength decreases, pH will increase.

In case of bases, the basic strength decreases, pH will decrease.

The process of froth floatation is used to separate mixture in which the components differ in their wetting properties, i.e. the ore is soluble in organic solvents like pine oil, while the impurity is soluble in water. The ore is separated out in the oil layer which being less dense floats on the water layer.
This separation is made more effective by centrifugation (agitating the mixture) either by blowing air into it or by mechanical stirring.

The given data explains how two different elements combining in definite proportions with the third element have a proportional combination with each other.

When sulphur and oxygen react with each other to form SO₂,
Mass of 'S' : Mass of 'O' = 10 : 10 = 1 : 1

The mixture of dust in air is a suspension. Smaller dust particles may remain suspended in the air and the larger ones are likely to settle under the effect of gravity. Dust particles form a significant portion of the suspended particulate matter in the air which is a major contributing factor for air pollution.

Metals are electropositive elements that react by losing electrons.

Across the period, the atomic radius decreases and consequently, the ionisation energy increases and the metallic character decreases.

Down the group, the atomic radius increases and consequently, the ionisation energy decreases and the metallic character increases.

Hence, Cs is the most metallic and Be is the least metallic element.

Law of multiple proportions, given by Dalton, states that when two elements combine to form more than one compound, then the mass of one element that combines with a fixed mass of the second in the different compounds is in a whole number ratio.