Best Answer
1 mole of a substance contains 6.022x10^23 "units" of that substance.
So 0.187 mol of Na+ is 1.13x10^23 ions (6.022x10^23 x 0.187).
The correct answer is a. This is because the pH of a solution is defined as -log10(concentration of H+ ions). An inverse logarithmic scale such as this means that a solution with a lower concentration of H+ ions will have a higher pH than one with a higher concentration. Therefore we know that the pH of the second sample will be higher than the first.
Since the logarithmic scale has the base 10, a change by 1 on the scale is a consequence of multiplication/division of the H+ concentration by a factor of 10. As the scale is inverse, this means that a decrease of concentration by factor 1000 is equivalent to increasing the pH by (1000/10) = 3.
Answer:
Option-D: 2.3 × 10⁻³ mol/dm³
Explanation:
Calculate moles of ascorbic acid,
Moles = Mass / M.Mass
Moles = 0.080 g / 176 g/mol
Moles = 0.00045 mole
Also,
Molarity = Moles / Vol. in dm³
Molarity = 0.00045 mol / 0.20 dm³
Molarity = 0.00227 mol.dm⁻¹ or 2.3 × 10⁻³ mol/dm³
Answer:
The configuration of the atom would be 2-8-2.
Explanation:
Any atom of an element combines with other element to complete its octet and become stable.
The electron configuration of the given atom is 2-8-6. That means the atom has 6 electrons in its outermost shell. To become stable the atom should have 8 electrons in its outermost shell. The given atom has 6 electrons so it either lose 6 electrons or gain 2 electrons to complete its octet.
But we know the atom having 5,6,7 electrons in its outermost shell they do not lose, they gain either 3 or 2 or 1 electrons to complete its octet.
So we say that atom with the electron configuration 2-8-6 bond with the atom having electron configuration 2-8-2.
