'Every action has an equal but opposite reaction' They are equal, but opposite.
Answer: The number to the left of AC should be 6.
Explanation: The balanced chemical reaction is one in which the number of atoms of each element on the reactant side must be equal to the number of atoms on product side.
The given equation 
is unbalanced as the atoms on the reactant side are not same as number of atoms on product side. This equation is called as skeletal equation.
The balanced chemical equation is :
Thus the number to the left of AC is 6.
By the object's composition and the acting agent to which factors the change of the substance or entity.
<span>The effect of physical property of matter on the object or substance can be better identified when the object doesn't change in composition or in nature. Unlike chemical property which has changed in its composition and atomic structure that was caused by chemical change or reaction due to an agent. Physical property is identified thru physical reactions or changes that has never changed the object in an atomic level, like cutting paper into smaller sizes. The aforementioned example illustrates physical proerty but being cut into smaller buts without changing the object from paper to any other substance, thus, its structure remain and its still called paper regardless of size, mass and texture. <span>
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Calculate the ratio by using Henderson-Hasselbalch equation:
pH = pKa + log [neutral form] / Protonated form
3.05 = 2.21 + log [neutral form] / [Protonated form]
3.05 - 2.21 = log [neutral form] / [Protonated form]
0.84 = log [neutral form] / [Protonated form]
[neutral form] / [protonated form] = anti log 0.84 = 6.91
