Answer: A=7 for the isotope with 4 neutrons.
Explanation:A lithium atom contains 3 protons in its nucleus. Notice that because the lithium atom always has 3 protons, the atomic number for lithium is always Z = 3. The mass number, however, is A = 6 for the isotope with 3 neutrons, and A = 7 for the isotope with 4 neutrons.
The volume of cylinder is 100 mL, inner diameter is 3.2 cm thus, radius will be:
Volume of layer formed=
...... (1)
Volume of layer is also equal to sum of volume of gasoline and water.
Density of gasoline is 
and mass is 34 g thus, volume of gasoline will be:
Now, density of water is 
and mass is 34 g thus, volume of water will be:
Adding both the volumes, volume of layer will be:
Putting the values in equation (1) to solve for height of the layer,
Thus, height of layer is 10.25 cm
The answer is D, pH greater than 7. This is because when you make a solution of potassium hydroxide, it leads to an excess of hydroxide ions in the water. Since the concentration of hydroxide ions is greater than that of protons, it causes the water to be basic. The basic range on the pH scale is always greater than 7.
Sorry if I'm wrong but I think that it is B.
