The answer is 14, 14 electrons can be contained in a f subshell.
The balanced equation for the reaction between KOH and HBr is as follows;
KOH + HBr --> KBr + H₂O
stoichiometry of KOH to HBr is 1:1
number of KOH moles reacted - 0.25 mol/L x 0.015 L = 0.00375 mol
according to molar ration
number of KOH moles reacted = number of HBr moles reacted
number of HBr moles reacted - 0.00375 mol
if 12 mL of HBr contains - 0.00375 mol
then 1000 mL of HBr contains - 0.00375 mol / 12 mL x 1000 mL = 0.313 mol
therefore molarity of HBr is 0.313 M
Answer: Option D is correct.
Explanation: Equation given by de Broglie is:

where,
= wavelength of the particle
h = Planck's constant
m = mass of the particle
v = velocity of the particle
In option A, football will have some mass and is moving with a velocity of 25 m/s, hence it will have some wavelength.
In Option B, unladen swallow also have some mass and is moving with a velocity of 38 km/hr, hence it will also have some wavelength.
In Option C, a person has some mass and is running with a velocity of 7 m/hr, hence it will also have some wavelength.
As, the momentum of these particles are large, therefore the wavelength will be of small magnitude and hence, is not observable.
From the above, it is clearly visible that all the options are having some wavelength, so option D is correct.
Answer:
For n=3 and l=1=p
It is 3p-orbital.
Magnetic quantum number m
l
have values from -l to +l and total of 2l+1 values.
Forl=1, m
l
values are:
m
l
=−1,0,1 for l=1; total m
l
values =3= Number of orbitals
Each orbital can occupy maximum of two electron
Number of electrons =2×3=6
Thus 6 electrons will show same quantum number values of n=3 and l=1.
Number of elements with last electron in 3p orbitals = 6