Chemistry - Complete P-block Question with Solution | TestHub
How many of the following statement(s) are true :
(i) concentrated turns yellow in sun light
(ii) A bottle of liquor ammonia should be cooled before opening
(iii) Nitrous oxide supports combustion more vigorously than air
(iv) is not hydrolysed but is readily hydrolysed
(v) Red phosphorus is denser and chemically less reactive than yellow phosphorus
(vi) is diatomic while phosphorus molecule is tetra atomic
Answer:
Solution:
All six statements are true.
(i) Concentrated decomposes in sunlight to form (brown gas), which dissolves to give a yellow color.
(ii) Cooling reduces the vapor pressure of ammonia, preventing its sudden escape upon opening.
(iii) contains 33.3% oxygen by weight, which is higher than air (23.2%), thus supporting combustion more vigorously.
(iv) is stable due to strong N-F bonds and lack of vacant d-orbitals on N. hydrolyzes readily due to the polarity of N-Cl bonds and the availability of d-orbitals on Cl (though the primary reason is the polarity and the ability of water to attack the nitrogen).
(v) Red phosphorus is a polymeric form, making it denser and less reactive than the discrete tetrahedral molecules of yellow phosphorus.
(vi) Nitrogen exists as diatomic due to strong triple bonds, while phosphorus forms tetra-atomic molecules (white phosphorus) or polymeric structures (red and black phosphorus).