A certain nuclide has a half-life of 40 days. If a sample containing 800 atoms is allowed to decay for 120 days how many atoms will remain undecayed?
A.50
B.100
C.200
D.400
Category: Chemical Engineering Mcqs
During the electrolysis of sodium chloride the anodic reaction is
A.oxidation of sodium ions
B.reduction of sodium ions
C.oxidation of chloride ions
D.reduction of chloride ions
Which of the following material has thermal conductivity closest to silver?
A.Copper
B.Brass
C.Aluminium
D.Steel
Incomplete combustion of hydrocarbon fuels may be due to
A.presence of high percentage of carbon monoxide in the flue-gas
B.a smoky stack
C.increased fuel consumption for the same heating requirement
D.all these answers
Which one of the following reactions does not take place at cathode ?
A.Cl- ? Cl+ e-
B.H+ + e- ? H
C.Ag+ + e- ? Ag
D.Cu2+ +2e- ? Cu
Isotopes of an element have same
A.mass number
B.number of neutrons
C.atomic weight
D.electronic configuration
The surface temperatures of a flat wall are 650?C and 450?C respectively and the thermal conductivity of the wall material is 0.30 kcal/m-hr-?C. The heat flux for a wall of 20 cm thickness will be
A.300 kcal/m2-hr
B.120 kcal/m2-hr
C.60 kcal/m2-hr
D.450 kcal/m2-hr
E.600 kcal/m2-hr
Ignition of liquid fuel at its flash point would cause
A.no combustion
B.continuous combustion
C.no momentary flash
