<span>
Evaporation occurred between the reaction of the hydrochloric acid and the arsenic group because there is a formation of gas. A
liquid is cooled if condensation exceeds evaporation. This is because the cooling of the liquid decreases the kinetic energy of the
molecules. Their movement is being restricted by the colder temperature. The
molecules tend to be closer with each other. Also, because of their restricted
movement, the liquid may turn into solid due the colder temperature. An example
of this is the cooling of liquid water by placing it into the refrigerator into
solid water (ice).</span>
Answer: A boron atom has 2 electrons at the first energy level and 3 electrons at the second energy level.
The pH of a solution that has a H⁺ ion concentration is 0.0039M is 2.4.
<h3>What is pH?</h3>
pH of any solution gives idea about the acidity or basicity of solution and it will be calculated as:
pH = -log[H⁺]
Given that, concentration of H⁺ ion = 0.0039 M
On putting tis value in pH equation, we get
pH = -log(0.0039)
pH = -(-2.4) = 2.4
Hence required value of pH is 2.4.
To know more about pH, visit the below link:
brainly.com/question/24595796
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