Question

Which property from following is NOT exhibited by interstitial compounds?

• A. Their melting points are higher than pure metal.
• B. Their densities are less than parent metal.
• C. Their chemical properties are different than parent metal.
• D. These are hard and good conductors of heat and electricity.

Hint:

Interstitial compounds like TiC, WC are extremely hard and have high melting points. Their densities are typically greater than the pure metal.

Answer 1

The Correct Option is B

Step 1: Understand the question.
Interstitial compounds form when small atoms like H, C or N slip into the gaps of a metal lattice. We must find the property they do NOT show.
Step 2: Recall their usual properties.
They have high melting points, are very hard, conduct heat and electricity well, and are more chemically inert than the plain metal.
Step 3: Think about density.
Extra small atoms fill the empty gaps and add mass without growing the lattice much. So the density usually goes up, not down.
Step 4: Check each statement.
Higher melting point is true. Different chemical behaviour is true. Hard and good conductor is true.
Step 5: Find the false one.
The claim that their density is less than the parent metal is false, since the trapped atoms add weight and raise the density.
Step 6: Choose the answer.
The property NOT shown is option 2. \[ \boxed{\text{Density less than parent metal (false)}} \]