Explanation

The element with the lowest electronegativity is francium (Fr),

With a Pauling scale electronegativity value of 0.7.

Electronegativity generally decreases down a group and increases across a period in the periodic table,

Making the most electropositive elements, like francium and cesium, the least electronegative. 

Explanation

Molarity is defined as the concentration of a solution expressed as the number of moles of solute per liter of solution.

It is a way to quantify how much solute is dissolved in a given amount of solution. 

Explanation

 Though fluorine is more electronegative, chlorine has the highest electron affinity due to less electron-electron repulsion.

Explanation

Carbon dioxide (CO2) reacts with calcium hydroxide (Ca(OH)2.

It is also known as lime water to form a white precipitate of calcium carbonate (CaCO3), which turns the solution milky:

Ca(OH)2 + CO2 → CaCO3 + H2O

This reaction is often used as a test for carbon dioxide.

Explanation

Sodium chloride (NaCl) forms ionic bonds, which are considered the strongest type of bonding in solids.

These bonds involve a strong electrostatic attraction between positively charged sodium ions (Na+) and negatively charged chlorine ions (Cl-).

This results in a stable crystal lattice structure, requiring a significant amount of energy to overcome and melt the compound. 

Explanation

Formic acid is present in the sting of ants.

It causes a sharp, burning sensation and irritation when injected into the skin during an ant sting.

Explanation

Protons: Have a positive charge.

Electrons: Have a negative charge.

Neutrons: Have no charge.

Positrons: A positively charged electron

Explanation

Silicon is obtained from sand, also known as silica (SiO2), by heating it with a carbon source in a furnace.

The options Lead, Isotope, and Uranium are incorrect because silicon is not directly obtained from them

Instead, silicon is a component of sand, and it exists in different isotopes. 

Explanation

A single displacement reaction is a type of chemical reaction where one element displaces another in a compound.

This displacement always involves a change in oxidation states,

Meaning one element is oxidized (loses electrons) while the other is reduced (gains electrons).

Therefore, a single displacement reaction is always a redox reaction. 

Explanation

When heated, lead nitrate decomposes into lead monoxide and nitrogen dioxide,

The red-brown gas is nitrogen dioxide, a product of decomposition. 

A decomposition reaction is a chemical reaction where a single compound breaks down into two or more simpler compounds.

In this case, lead nitrate (Pb(NO3)2) breaks down into lead monoxide (PbO) and nitrogen dioxide (NO2) when heated.