Atoms or molecule after gaining of electron possesses negative charge and is known as anion.
For the given sets:
The given elements are alkali metals and have tendency to lose electrons easily and form cations.
The given elements are non-metals and are electronegative. So, they gain electrons easily and form anion.
Carbon has tendency to form bond by sharing of electrons, Sulfur has tendency to gain electrons and form anion whereas Lead has tendency to lose electron.
Potassium and Iron has tendency to lose electron and form cation whereas Bromine has tendency to gain electron to form anion.
Hence, from the given sets, all elements of set: 
have tendency to form anions in binary ionic compounds.
1: True
2: True
3: False
4: False
(Question 2 might not be true, not sure)
A
nswer: -
C. Energy is released by the reaction
Explanation:-
An exothermic reaction is one in which during the progress of the reaction heat is evolved.
So energy is released by the reaction.
It cannot be created as energy is neither created nor destroyed as per the Law of conservation of energy. Energy is not transferred either.
The energy released during the progress of the reaction originates from the chemical bonds of the reactants as they break during their conversion into products.
<span>The density of the solution =1.05 g/ml.
</span><span>The total mass of the resulting solution is = 398.7 g (CaCl2 + water)
</span>
Find moles of CaCl2 and water.
Molar mass of CaCl2 = 110 (approx.)
Moles of CaCl2 = 23.7 / 110 = 0.22
so, moles of Cl- ion = 2 x 0.22 = 0.44 (because each molecule of CaCl2 will give two Cl- ions)
Moles of water = 375 / 18 = 20.83
Now, Mole fraction of CaCl2 = (moles of CaCl2) / (total moles)
total moles = moles of Cl- ions + moles of Ca2+ ions + moles of water
= 0.44 + 0.22 + 20.83
=21.49
So, mole fraction = 0.44 / (21.49) = 0.02
Guess what !!! density is not used. No need
Answer:
A. 30
Explanation:
Retinol is the chemical form of Vitamin A. It has a chemical formula of C20H30O.
It is processed when retinyl palmitate is broken down in the small intestine. Retinol helps in the proper regulation of eye cells hence a vital component in ensuring good eye sight.
It also helps in the neutralization of free radicals in the body and acts as an antioxidant which prevents cells of the body from ageing.
