Saved Bookmarks
| 1. |
Kevlar is a nylon obtained by condensation polymerization of 1, 4- diaminobenzene and 1, 4-benenedicarboxylic acid. Its fibres are five times stronger than steel & hence are used for making bullet-proof vests. There are two compounds of boron which are also used for making bullet-proof vests. Now answer the following questions. (i) Name the two compounds of boron which are used for making bullet-proof vests and how are they prepared ? (ii) What are the other advantages of using boron based compounds over Kevlar for making bullet-proof vests ? |
|
Answer» (i) The compounds of boron which are used for making bullet-proof vests are : boron nitride (BN) and boron carbide (B4C). These are prepared from boron oxide as follows : B2O3 + 2NH3 → 2BN + 3 H2O (T = 1173 K) 2B2O3 + 7C → B4C + 6CO (T = 1873 K) (ii) Boron has high ability to absorb neutrons and hence boron carbide or boron nitride based bullet-proof vests can also act as protective shield against radioactive radiations. |
|