Answer:
0.6749 M is the concentration of B after 50 minutes.
Explanation:
A → B
Half life of the reaction = 
Rate constant of the reaction = k
For first order reaction, half life and half life are related by:
Initial concentration of A = ![[A]_o=0.900 M](https://tex.z-dn.net/?f=%5BA%5D_o%3D0.900%20M)
Final concentration of A after 50 minutes = ![[A]=?](https://tex.z-dn.net/?f=%5BA%5D%3D%3F)
t = 50 minute
![[A]=[A]_o\times e^{-kt}](https://tex.z-dn.net/?f=%5BA%5D%3D%5BA%5D_o%5Ctimes%20e%5E%7B-kt%7D)
![[A]=0.900 M\times e^{-0.02772 min^{-1}\times 50 minutes}](https://tex.z-dn.net/?f=%5BA%5D%3D0.900%20M%5Ctimes%20e%5E%7B-0.02772%20min%5E%7B-1%7D%5Ctimes%2050%20minutes%7D)
[A] = 0.2251 M
The concentration of A after 50 minutes = 0.2251 M
The concentration of B after 50 minutes = 0.900 M - 0.2251 M = 0.6749 M
0.6749 M is the concentration of B after 50 minutes.
The charge of a Rb ion would be +1
Answer : The correct option is, (C) 10-mL volumeric pipet.
Explanation :
Graduated cylinder : It is a measuring cylinder that is used to measure the volume of a liquid. It has a narrow cylindrical shape. The marked line drawn on the graduated cylinder shows the amount of liquid that has been measured.
Pipet : It is a type of laboratory equipment that is used to measure the volume of a liquid. It is small glass tube and the marked line drawn on the pipet. It is used to accurately measure and transfer of volume of liquid from one container to another.
Volumetric flask : It is a type of laboratory tool that is also used for measuring the volume of liquid. It is used to make up a solution to a known volume. It measure volumes much more precisely than beakers.
Beaker : It is a type of laboratory equipment that has cylindrical shape and it is used for the mixing, stirring, and heating of chemicals.
As per question, we conclude that the pipet is most precise than other devices because in pipet the marking lines are more accurate. Thus, it can be used to measure volume to precision.
Hence, the correct option is, (C) 10-mL volumeric pipet.
We can skip option B and D because NaCl is salt and H₂SO₄ is a strong acid.
Neutralization reactions are those reactions in which acid and base react to form salt and water.
As water being amphoteric in nature can react with HCl as follow,
HCl + H₂O ⇆ H₃O⁺ + OH⁻
In this case no salt is formed, so we can skip this option.
Ammonia being a weak base can abstract proton from HCl as follow,
HCl + NH₃ → NH₄Cl
Ammonium Chloride is a salt. So, among all four options, Option-C is the correct answer.
