Answer : The correct option is, (B) 
Solution :
According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.

or,
..........(1)
where,
= rate of effusion of unknown gas = 
= rate of effusion of oxygen gas = 
= molar mass of unknown gas = ?
= molar mass of oxygen gas = 32 g/mole
Now put all the given values in the above formula 1, we get:


The unknown gas could be carbon dioxide
that has approximately 44 g/mole of molar mass.
Thus, the unknown gas could be carbon dioxide 
Answer:
The answer to your question is letter B. Phosphoric acid
Explanation:
A. water is not the right answer because it has a density of 1 g/ml and water is a liquid not a solid.
B. phosphoric acid is the right answer because phosphoric acid is a solid and all solids have a density higher than water (1 g/ml)
C. sodium hydroxide could be the correct answer but it is not because the crystals of sodium hydroxide are more colorless than white.
I see you have access to the internet. Google 'Kelvin to C', and input 251. You'll get -22.15.
The correct answer would be the first one. The reaction that will not conduct electricity would be CH3OH(l) = CH3OH(aq) since it stays as a single molecule in solution. It does not have any free electrons that will allow the flow of current into the solution. Other options dissociates into ions which has free electrons so they allow current to flow.
Answer:
A.It lowers the melting point of alumina. B.It increases the electrical conductivity. ... Hint: The solution of alumina and cryolite during the electrolysis gives the aluminium at cathode and oxygen at anode. The alumina is a poor conductor of electricity and the fusion temperature of alumina is about 2000∘C.