Answer:
6H2 + P4→ 4PH3
Explanation:
Phosphorus has 4 in it and hydrogen has 3 in it. in order to balance it, we have to put 4 in front of phosphine so that the phosphorus on the product side has an equal amount as to the one on the reactant side.
the only one left to balance is hydrogen and so in order to balance it we put a 6 on h2 because the hydrogen in the product size becomes 12 (4 * 3).
therefore the hydrogen on the reactant side becomes 12 as well (6 * 2)
Answer : The correct option is, (b) 22.5 M
Explanation : Given,
Mass of calcium nitrate tetrahydrate = 266 g
Molar mass of calcium nitrate tetrahydrate = 236.15 g/mole
Volume of solution = 
Molarity : It is defined as the moles of solute present in one liter of solution.
Formula used :

Now put all the given values in this formula, we get:

As calcium nitrate tetrahydrate dissociate to give 1 mole of calcium ion, 2 moles of nitrate ion and 4 moles of water.
The concentration of nitrate ion = 
Thus, the concentration of nitrate ion is, 22.5 M
32.066 atomic mass units.
Gas.
The sky is not solid, not liquid but of gas. It is also
called the atmosphere, one of the important spheres on earth that influences
the climate –temperature, humidity, precipitation, atmospheric pressure, and
the biotic community as a whole. The atmosphere or the sky is composed of many
layers and is responsible to protecting the living organisms of the earth
against the deadly ultraviolet rays and other strong radiation coming from the
sun.
A chemical reaction happens when the atoms or molecules rearrange to form a new substance