Which of the following alloys contain iron?
Duralumin and steel
Brass and bronze
Steel and permalloy
Soft solder and duralumin
Correct answer is C
No explanation has been provided for this answer.
In a flame test for calcium, the flame appears
green when viewed through a blue glass
blue when viewed through a blue glass
orange -red when viewed through a blue glass
brick-red when viewed through a blue-glass
Correct answer is A
When a Calcium compound is held in a non-luminous Bunsen flame and viewed directly with the naked eye, it is seen as brick red,then as light green as seen through blue glass.
The property used in the industrial preparation of nitrogen and oxygen from air is?
rate of diffusion
density
boiling point
solubility
Correct answer is C
Fractional distillation of liquefied air, with Nitrogen distilling as a vapor at a lower boiling point of -196°C while O2 is left as a liquid.
The ores that can be concentrated by flotation are
nitride ores
sulphide ores
oxide ores
non-metals
Correct answer is B
No explanation has been provided for this answer.
Metalliods are also referred to as
semi-metals
metals
colliods
non-metals
Correct answer is A
No explanation has been provided for this answer.