Questions & Answers
Question
Answers
Related Questions
What $[O{{H}^{-}}]$ in the final solution prepared by mixing 20 mL of 0.05M HCl with 30mL of 0.10M $Ba{{(OH)}_{2}}$ ?
A. 0.12M
B. 0.10M
C. 0.40M
D. 0.005M
Answer
![Verified]()
Verified
Verified
Hint: The reactant that fully reacts in the reaction is called reactant limiting or reagent limiting. The reactant that is not fully consumed in the reaction is called excess reactant. Write the balanced reaction equation before solving the question. A balanced equation is an equation for a chemical reaction in which the number of atoms in the reaction for each element and the total charge for both the reactants and the products is equal.
Complete answer:
The reaction used in question is:
$Ba{{(OH)}_{2}}+HCl\to BaC{{l}_{2}}+2{{H}_{2}}O$
Number of moles of ${{H}^{+}}$ ions present in solution = concentration of HCl $\times $ Volume of HCl
$=0.05\times \dfrac{20}{1000}=0.001$ moles
There are two $O{{H}^{-}}$ ions in one molecule of $Ba{{(OH)}_{2}}$.
$O{{H}^{-}}$ ions released in the Barium Hydroxide solution = concentration of $Ba{{(OH)}_{2}}$ $\times $ Volume of $Ba{{(OH)}_{2}}$ $\times $ 2.
$[O{{H}^{-}}]$ = $0.1\times \dfrac{30}{1000}\times 2=0.006$ moles.
${{H}^{+}}$ ion is limiting reagent.
Therefore, 0.001 moles of ${{H}^{+}}$ and $O{{H}^{-}}$ combine to form water.
0.005 moles of ions are $O{{H}^{-}}$ remaining.
Molarity is defined as the number of moles of solute dissolved in one litre (or one cubic decimeter) of solution. It is denoted by M.
Molarity, $M=\dfrac{n}{V}$ where, n is the number of moles and v is the volume of the solution.
Total volume of the solution = (20 + 30) mL = 50 mL = 0.05L.
Hence, the molarity of $O{{H}^{-}}$ ion = $\dfrac{0.005moles}{0.05L}$ = 0.100M
So, the correct answer is “Option B”.
Note: Don’t get confused between molarity and molality. Molarity (M) is defined as the number of moles of solute dissolved in one litre of solution whereas Molality (m) is defined as number of moles of solute per kilogram (kg) of the solvent.
For avoiding calculation mistake convert all quantities into SI unit before calculation
Complete answer:
The reaction used in question is:
$Ba{{(OH)}_{2}}+HCl\to BaC{{l}_{2}}+2{{H}_{2}}O$
Number of moles of ${{H}^{+}}$ ions present in solution = concentration of HCl $\times $ Volume of HCl
$=0.05\times \dfrac{20}{1000}=0.001$ moles
There are two $O{{H}^{-}}$ ions in one molecule of $Ba{{(OH)}_{2}}$.
$O{{H}^{-}}$ ions released in the Barium Hydroxide solution = concentration of $Ba{{(OH)}_{2}}$ $\times $ Volume of $Ba{{(OH)}_{2}}$ $\times $ 2.
$[O{{H}^{-}}]$ = $0.1\times \dfrac{30}{1000}\times 2=0.006$ moles.
${{H}^{+}}$ ion is limiting reagent.
Therefore, 0.001 moles of ${{H}^{+}}$ and $O{{H}^{-}}$ combine to form water.
0.005 moles of ions are $O{{H}^{-}}$ remaining.
Molarity is defined as the number of moles of solute dissolved in one litre (or one cubic decimeter) of solution. It is denoted by M.
Molarity, $M=\dfrac{n}{V}$ where, n is the number of moles and v is the volume of the solution.
Total volume of the solution = (20 + 30) mL = 50 mL = 0.05L.
Hence, the molarity of $O{{H}^{-}}$ ion = $\dfrac{0.005moles}{0.05L}$ = 0.100M
So, the correct answer is “Option B”.
Note: Don’t get confused between molarity and molality. Molarity (M) is defined as the number of moles of solute dissolved in one litre of solution whereas Molality (m) is defined as number of moles of solute per kilogram (kg) of the solvent.
For avoiding calculation mistake convert all quantities into SI unit before calculation
Like this
Liked
-
LIVECourses
-
V PRO
-
JEE
-
JEE Main & Advanced 2021
-
JEE Main & Advanced 2022
-
-
NEET
-
NEET 2021
-
NEET 2022
-
-
CBSE
-
Class 6
-
Class 7
-
Class 8
-
Class 9
-
Class 10
-
Class 11
-
Class 12
-
-
ICSE
-
Class 9
-
Class 10
-
-
Maharashtra Board
-
Class 9
-
Class 10
-
-
Micro Courses
-
-
PREMIUM1-on-1 Classes
-
Study Material
-
NCERT Solutions
-
Previous Year Papers
-
Mock Tests
-
Sample Papers
-
Reference Book Solutions
-
ICSE Solutions
-
School Syllabus
-
Revision Notes
-
Important Questions
-
Math Formula Sheets
-
-
More
Book your FREE Online counselling session
Share your contact information
Your FREE Online counselling session has been booked!
Vedantu academic counsellor will be calling you shortly for your Online Counselling session.
DONE
Please try again later
OK
NCERT Book Solutions
Reference Book Solutions
Toll Free:
1800-120-456-456
Mobile:
+91 988-660-2456
Toll Free:
1800-120-456-456
Mobile:
+91 988-660-2456
(Mon-Sun: 9am - 11pm IST)
Questions?
Chat with us
