Coffee stains can best be removed by?
Kerosine
turpentine
a solution of borax in water
ammonia solution
Correct answer is C
Borax solution refers to sodium borax in water. it is used for cleaning purposes. borax is mildly alkaline and can help break down acidic stains, such as those from coffee
Substance employed as drying agents are usually?
amphoteric
hygroscopic
efflorescent
acidic
Correct answer is B
No explanation has been provided for this answer.
Permanent hardness of water can be removed by?
filtration
adding slaked lime
adding caustic soda
boiling
Correct answer is C
- this hardness cannot be removed by boiling. We can remove this hardness by treating the water with washing soda, caustic soda and permutit
A noble gas with a high power of fog penetration used in aerodrome beacons is?
krpton
argon
helium
neon
Correct answer is D
No explanation has been provided for this answer.