<u>Answer:</u>
Exothermic Reaction are those reaction, in which energy is released while in endothermic reaction are those, in which energy is absorbed.
<u>Explanation:</u>
First Reaction:
As in this reaction, energy is released
½H2(g) + ½I2(g) → HI(g), ΔH = +6.2 kcal/mole
so it is <em>exothermic reaction</em>
Second reaction:
As in this reaction, energy is absorbed
21.0 kcal/mole + C(s) + 2S(s) → CS2(l)
so it is <em>endothermic reactions</em>.
•The atomic number of an atom is the number of protons it has. If the atomic number is 20 then we know the atom has 20 protons.
•The mass number of an atom is the total number of protons and neutrons the atom contains. The mass number is 41 and the number of protons is 20, just subtract 20 from 41 and you will get the number of neutrons: 41 - 20= 21. The atoms has 21 neutrons.
•The number of electrons found in an atom is equal to the number of protons. The atoms has 20 protons which means it has 20 electrons.
So, the answer is:
B) 20 protons, 20 electrons, and 21 neutrons
The compound solubility which will not be affected by a low pH in solution is AgBr.
<h3>What is pH?</h3>
pH is a measure of the acidity or basicity of any solution and according to the pH scale 0 to 6.9 shows the acidity, 7 is neutral and 7.1 to 14 shows the basicity of any solution.
- AgBr is sparingly soluble in water and not soluble in acids, so if we low the pH of the solution towards the acidity its solubility not affected.
- NiCO₃ is a basic salt and and shows solubility in the acidic medium so change in pH will affect its solubility.
- Co(OH)₂ it is also a basic compound and shows its solubility in the acidic medium and get affected when change in pH takes place.
- PbF₂ is a strong base and also shows solubility in the acidic medium easily, so get affected when change in pH takes place.
- In CuS, sulphide is basic ion and whole compound shows solubility in the acidic medium and get affected when low pH of solution takes place.
AgBr is not affected by a low pH in solution.
To know more about solubility, visit the below link:
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