Questions

In vulcanization, cruder rubber is heated with 3% sulphur at about for 1200C for 2-3 hours.

Vulcanised rubber is a vastly improved product.

A place where government records are kept are called Archives.

One who dies for a noble cause is called a martyr. He is a person who dies fighting for what they believe in like advocating religious or other beliefs, refusing to renounce, etc...

Ionic character depends on the electronegativity difference between the bonding elements. The greatest the elctronegativity diffference the greatest the ionic character.

Here in the given options, H-F has has the greatest ionic character. The electronegativity of Hydrogen is 2.1 and that of Fluorine is 4. Now the electronegativity difference is 4 - 2.1 = 1.9.

The missing number in the given number puzzle is "78".

Here the logic is the numbers are from 86 - 91 when we read upside down.