answer both rhe questions please
Answers
16.1.Graphite is used as a lubricant due to its slippery nature. Graphite has layers of carbon atoms, with weak force.
2.Diamonds is used abrasive because diamond are very hard they are often used as an abrasive.
3.Aluminium alloys are used to make aircraft because the metal resists corrosion, some airlines don't paint their planes, saving several hundred of kilograms in weight.
17.i) boron does not have d-orbitals in its Valencia shell.and therefore the maximum Covalency of boron cannot be exceed 4.the compound is unstable to form BF63 ions.
ii) the main reasons are:
1.six large chloride ions cannot be accommodated around Si4+ due to limitation if its size
2.interaction between
long pair of chloride ion and Si4+ is not very strong.
3.Being a strong oxidising agent,nitric acid can react with compound such asl cyanides,carbides or metallic powders explosively and with many other organic compounds such as turpentine,violently and Hypergolically(i.e that Self-igniting) hence it should be stored away from bases and organics.
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