Question

Which of the following is not a co-polymer?

• A. Buna-S rubber
• B. Neoprene rubber
• C. Bakelite
• D. Urea - Formaldehyde

Hint:

The names of some polymers give clues to their composition.
"Buna-S" stands for Butadiene-Styrene.
Names like "Urea-Formaldehyde" explicitly state the two monomers.
When a polymer is named after a single monomer, like Polystyrene or Neoprene (polychloroprene), it's a homopolymer.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
We need to evaluate the hardness of the given water sample in terms of CaCO₃ equivalent.

Step 2: Key Formula or Approach:
Convert MgCl₂ into CaCO₃ equivalent and calculate the concentration in ppm.

Step 3: Detailed Explanation:
The water contains 19 mg of MgCl₂ in 2 kg. The equivalent CaCO₃ mass is \(19\times100/95=20\) mg. Hence, hardness equals \(20/2=10\) mg/kg, which is numerically equal to 10 ppm.

Step 4: Final Answer:
The hardness value is 10 ppm.