I choose the option A.
The electron absorbs energy from specific wavelength then moving from a lower energy orbital to a higher energy orbital.
A solution of K2SO4 and KCl is added to a solution of Ba(NO3)2. BaS0₄ (s) will precipitate out of this combined solution.
Molecular equation
K2SO4(aq) + Ba(NO3)2(aq) → BaSO4(s) + 2 KNO3(aq)?
This equation represents a double displacement (replacement) reaction, also called a metathesis reaction, in which the reactant ions exchange places to form new products. The general equation is:
A-B + C-D → A-D + C-B;
where A and C are cations, and B and D are anions.
Complete ionic equation: Includes all ions and the precipitate.
2K^+(aq) + SO4^2-(aq) + Ba^2+(aq) + 2[NO3]^-(aq) → 2K^+(aq) + 2[NO3]^- + BaSO4(s)
In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution.
The solid formed is called the precipitate. In case of an inorganic chemical reaction leading to precipitation, the chemical reagent causing the solid to form is called the precipitant.
Learn more about precipitation here : brainly.com/question/1783904
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There is a special temperature for every substance called the melting point. When a solid reaches the temperature of its melting point, it can become a liquid.
Answer: Molar concentration of the tree sap have to be 0.783 M
Explanation:
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:
where,
= osmotic pressure of the solution = 19.6 atm
i = Van't hoff factor = 1 (for non-electrolytes)
R = Gas constant = 
T = temperature of the solution = ![32^oC=[273+32]=305K](https://tex.z-dn.net/?f=32%5EoC%3D%5B273%2B32%5D%3D305K)
Putting values in above equation, we get:
Thus the molar concentration of the tree sap have to be 0.783 M to achieve this pressure on a day when the temperature is 32°C
