Answer:
The Two reasons are :-
1. Combustion efficiency
2. Standardization of test conditions as non-luminous flame.
Explanation:
A luminous flame isn't suitable for heating as it gives out soot (A black powdery or flaky substance consisting largely of amorphous carbon, produced by the incomplete burning of organic matter)
The answers is ATP it took me a long time to find it but here you go. hope i helped
Molarity is defined as the moles of solute per liter of solution. 
. Where M is molarity, n is the number of moles and V is the volume. First we must find the molar mass of 
which is 109.98 g/mol
Then we find the molarity using above equation
D. photons it contains light but with zero mass
