Answer:
A. O=C=O and O≡C−O
Explanation:
Resonance:
When the electron distribution on the molecule become uneven like one molecule have more electron compare to other.Resonance occurs due to overlap of the orbitals.When electron flow through pi system then resonance occurs.
So the option A is correct.
A. O=C=O and O≡C−O
Density = mass/volume
D = 40/80 = 0.5g
D= 0.5g
Mass Molar of

Ca = 3*40 = 120 amu
P = 2*31= 62 amu
O = (16*4)*2 = 64*2 = 128 amu
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Mass Molar of

= 120 + 62 + 128 = 310 g/mol
Therefore: <span>What is the gram formula mass of Ca3(PO4)2 ?
</span>Answer:
310 grams
H is 4*10^6 M , OH is 2.5*10^-9 M