An aqueous solution of urea containing 18g urea in 1500 cm3 of the solution has a density equal to 1.052. If the molecular weight of urea is 60, the molality of the solution is
0.200
0.192
0.100
1.200
The heat of neutralisation of a strong acid and a strong alkali is 57.0 kJ mol-1.The heat released when 0.5 mole of HNO3 solution is mixed with 0.2 mole of KOH is
57.0 kJ
11.4 kJ
28.5 kJ
34.9 kJ
90Th228 emits four alpha and one beta particles. Number of neutrons in daughter element is
129
190
232
138
The heat of combustion of carbon is - 393.5 kJ/mol. The heat released upon the formation of 35.2 g of CO2 from carbon and oxygen gas is
+ 315 kJ
- 31.5 kJ
- 315 kJ
+ 31.5 kJ
The central carbon atom of a free radical contains
6 electrons
7 electrons
8 electrons
10 electrons
B.
7 electrons
The central carbon atom of a free radical contains seven electrons. Free radicals are paramagnetic due to the presence of an unpaired electron and are formed by homolysis of covalent bonds either by heat or by light.