Answer : The retention time is, 20 min
Explanation :
Retention time : It is defined as the amount of time a compound spends on the column after it has been injected.
Formula of retention time is:

Given:
Distance from injection point to center of peaks = 10 cm
Chart recorded speed = 0.5 cm/min
Now put all the given values in the above formula, we get:

Retention time = 20 min
Thus, the retention time is, 20 min
Answer:
Energy
Explanation:
Between gas to liquid, or liquid to gas, will give off extra energy to the surrounding environment
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Answer:
adding an acidic solution
Explanation:
Strong acids dissociate completely in water and the H⁺ ions react with the OH⁻ ions to make H₂O. If we add an acid to our solution of Ca(OH)₂, the acid protons would react with some of the OH⁻ ions and drive the equilibrium to the right. More of the solid Ca(OH)₂ should dissolve.