Explanation

The permanent hardness of water is due to the presence of MgSO₄ (magnesium sulfate).

Permanent hardness is caused by dissolved minerals like calcium sulfate (CaSO₄) and magnesium sulfate, which cannot be removed by boiling the water.

Explanation

CH3-CH2-CH3 is the molecular formula for propane, which is a saturated hydrocarbon (an alkane).

Explanation

• Noble gases are stable because their outermost energy level is full, meaning they have eight electrons in their valence shell.
• This full outer energy level gives them a stable electronic configuration, similar to that of the noble gases, and makes them unreactive.

Explanation

• The number of protons and neutrons in an atom are added together to obtain the total number of nucleons.
• It is also known as the mass number.

Explanation

 Alkali metals are found in Group 1 of the periodic table.

Potassium (K) is located in Group 1, making it an alkali metal. 

Explanation

The assembly of the 40S and 60S subunits of the ribosome creates an 80S unit. 

80S unit:

This is the complete functional ribosome in eukaryotic cells, composed of the smaller 40S subunit and the larger 60S subunit. 

Explanation

An oxidizing agent readily accepts electrons, and higher oxidation states of a metal generally indicate a greater tendency to gain electrons and act as an oxidizing agent. 

Mn⁴⁺:

While not as strong as MnO4-, Mn4+ is still a potent oxidizing agent due to its high oxidation state. 

Mn³⁺:

This ion is considered a particularly strong oxidizing agent because it readily reduces to Mn²+, a more stable configuration. 

Mn⁷⁺:

In the form of permanganate ion (MnO₄⁻), Mn⁷+ is the strongest oxidizing agent among the listed options.

It has the highest oxidation state of manganese and readily accepts electrons. 

Explanation

All gases will start effusing at the same time, but the rate of effusion depends on their molar mass (Graham’s Law).  

Lighter gases like H₂ effuse faster than heavier ones like Cl₂.

Explanation

The atomic mass of sodium is 23 g/mol.  

- This means 1 mole (6.022 × 10²³ atoms) of sodium weighs 23 grams.  

- So, the mass of one atom of sodium is:

= 23 g / Nₐ  

= 23 / (6.022 × 10²³) grams

So the correct option is: 23 / Nₐ g.

Explanation

Each molecule of water (H₂O) has 10 electrons (2 from hydrogen and 8 from oxygen).

Therefore, 1 mole of water has 10 moles of electrons.

So, 10 moles of water have 10 x 10 = 100 moles of electrons.