Answer:
Oxygen
Explanation:
If two balloons are filled with hydrogen gas and helium gas respectively, then we want to identify what gas is in each balloon, we have to do so by exposing the both balloons to flame in an oxygen atmosphere.
Hydrogen combines with oxygen in the presence of a flame with quite a loud sound and the flame is sustained but when a flame is brought near helium gas in a balloon, the gas will only make a little sound when exposed to the flame and extinguish the flame.
The reason for the explosion of the gas in the hydrogen balloon is that combustion of hydrogen gas is exothermic. The heating up of surrounding air molecules leads to a sudden explosion.
However, the helium balloon makes a little sound when the balloon is ruptured releasing helium gas which extinguishes the flame.
Explanation:
Let us assume that total mass of the solution is 100 g. And, as it is given that acetic acid solution is 12% by mass which means that mass of acetic acid is 12 g and 88 g is the water.
Now, calculate the number of moles of acetic acid as its molar mass is 60 g/mol.
No. of moles =
= 
= 0.2 mol
Molarity of acetic acid is calculated as follows.
Density = 
1 g/ml = 
volume = 100 ml
Hence, molarity = 
= 
= 2 mol/l
As reaction equation for the given reaction is as follows.

So, moles of NaOH = moles of acetic acid
Let us suppose that moles of NaOH are "x".
(as 1 L = 1000 ml)
x = 20 L
Thus, we can conclude that volume of NaOH required is 20 ml.
Answer with Explanation:
This is expirament based Q
1) Bring a magnet near ... the Cobalt will come out of te mixture and get attracted to magnet
2) Disolve it in a solution of ethanol. The Idoine gets dissolve and the other doesnt.
Hope im right!!