An elements used in production of matches is
nitrogen
aluminum
copper
sulphur
Correct answer is D
Sulphur is an element that burns with a strongly explosive smell, as a result it is explosive smell
The weakest attractive force that can be observed between two molecules is
ionic
covalent
co-ordinate covalent
vander Waals
Correct answer is D
Vander Waals are the weakest attractive forces that exist between two molecules. Option A,B,C are not weak forces because the force attraction that exist between their interested molecule are very strong
Which of the noble gases has the greatest ionization energy
He
Xe
Ar
Rr
Correct answer is A
Ionization energy: The amount of energy required to remove an electron from an isolated atom or molecule.
Trends down group :
1
2
3
4
Correct answer is C
Ozone means Oz as the atomicity is 3. Option A,B,D cannot give ozone because their atomicity is not 3
efflorescence
déliquescence
effervescence
fluorescence
Correct answer is A
Efflorescence is a process of long exposure to the atmosphere which favors salt loss of water. Options B, C, D are not related to loss of water