Answer: Option (A) is the correct answer.
Explanation:
A covalent bond is formed when there occurs sharing of electrons between atoms.
For example, in hydrogen atom there is one electron in its orbit and in a chlorine atom there is 7 valence electron. So, in order to attain stability both hydrogen and chlorine share electrons when they come close to each other.
Whereas except hydrogen and chlorine rest of the given atoms will form ionic bond, that is, bond formed by transfer of electrons.
Thus, we can conclude that a pair of hydrogen and chlorine will form a covalent bond.
The average human has between sixty trillion and ninety trillion cells, but there are also organisms that have only a single cell. So basically it depends on the type of organism, but the minimum amount of cells is one.
pH=2.7
<h3>Further explanation</h3>
Acetic acid = weak acid
![\tt [H^+]=\sqrt{Ka.M}](https://tex.z-dn.net/?f=%5Ctt%20%5BH%5E%2B%5D%3D%5Csqrt%7BKa.M%7D)
Ka = acid ionization constant
M = molarity
Ka for Acetic acid(CH₃COOH) : 1.8 x 10⁻⁵
![\tt [H^+]=\sqrt{1.8\times 10^{-5}\times 0.222}\\\\=0.001998=1.998\times 10^{-3}](https://tex.z-dn.net/?f=%5Ctt%20%5BH%5E%2B%5D%3D%5Csqrt%7B1.8%5Ctimes%2010%5E%7B-5%7D%5Ctimes%200.222%7D%5C%5C%5C%5C%3D0.001998%3D1.998%5Ctimes%2010%5E%7B-3%7D)

Answer:
Fe2O3 + __3_H2O --> __2_Fe(OH)3
Explanation:
____Fe2O3 + __3_H2O --> __2_Fe(OH)3
Fe -2 Fe -2
H - 6 H - 6
O - 6 O- 6
Powered sulfur is yellow, and powdered iron is gray. When powered sulfur are mixed at 20 degrees C, the powered iron remains magnetic.