Substances have different tendencies to donate or accept electrons. When a really good donor meets a great acceptor, the chemical reaction releases a lot of energy. Oxygen (O2) is the best electron acceptor and is used in many aerobic reactions (reactions with oxygen). Hydrogen gas (H2) is a good electron donor.
When O2 and H2 are combined, along with a catalyst, water (H2O) is formed. This example of a redox reaction can be written like this:

1.95 or 2 is the molarity of a 45.3g sample of KNO3 (101g) dissolved in enough water to make a 0.225L solution.
The correct answer is option b
Explanation:
Data given:
mass of KN
= 45.3 grams
volume = 0.225 litre
molarity =?
atomic mass of KNO3 = 101 grams/mole
molarity is calculated by using the formula:
molarity = 
first the number of moles present in the given mass is calculated as:
number of moles = 
number of moles = 
0.44 moles of KNO3
Putting the values in the equation of molarity:
molarity = 
molarity = 1.95
It can be taken as 2.
The molarity of the potassium nitrate solution is 2.
Air & noise pollution
Quarry waste
Damage to biodiversity
The wrong answers for sure are B and D, I assume the answer is C
Answer: The molality of solution is 17.6 mole/kg
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
where,
n = moles of solute
= weight of solvent in kg
moles of acetone (solute) = 0.241
moles of water (solvent )= (1-0.241) = 0.759
mass of water (solvent )=
Now put all the given values in the formula of molality, we get
Therefore, the molality of solution is 17.6 mole/kg