KCET · Chemistry · Electrochemistry
The approximate time duration in hours to electroplate 30 of calcium from molten calcium chloride using a current of \(5 \mathrm{~A}\) is [At. mass of \(\mathrm{Ca}=40\) ]
- A 80
- B 10
- C 16
- D 8
Answer & Solution
Correct Answer
(D) 8
Step-by-step Solution
Detailed explanation
\(\mathrm{Ca}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Ca}\) (at cathode)
\(1 \mathrm{~mol} \mathrm{} \mathrm{CaCl}_{2}=2 \mathrm{~F}\)
From \(Q=i t\)
\(\mathrm{n} \cdot 2 \mathrm{~F}=\mathrm{it}\)
\(t=\frac{n \cdot 2 F}{i}\)
\(=\frac{30}{40} \times \frac{2 \times 96500}{5}=28950 \mathrm{~s}\)
\[
=\frac{28950}{60 \times 60} \mathrm{~h}=8.04 \mathrm{~h}
\]
\(1 \mathrm{~mol} \mathrm{} \mathrm{CaCl}_{2}=2 \mathrm{~F}\)
From \(Q=i t\)
\(\mathrm{n} \cdot 2 \mathrm{~F}=\mathrm{it}\)
\(t=\frac{n \cdot 2 F}{i}\)
\(=\frac{30}{40} \times \frac{2 \times 96500}{5}=28950 \mathrm{~s}\)
\[
=\frac{28950}{60 \times 60} \mathrm{~h}=8.04 \mathrm{~h}
\]
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Chemistry
- Hydroxyl ion concentration of \(10^{-2} \mathrm{M} \mathrm{HCl}\) isKCET 2007 Easy
- The vitamin that helps in clotting of blood isKCET 2019 Easy
- The reagent ' \( X \) ' used for the following reaction is
KCET 2018 Medium - \(20 \mathrm{~mL}\) of methane is completely burnt using \(50 \mathrm{~mL}\) of oxygen. The volume of the gas left after cooling to room temperature isKCET 2012 Medium
- Intramolecular hydrogen bonding is formed inKCET 2013 Easy
- The compound with molecular formula \(\text{C}_{20}\text{H}_{42}\) isKCET 2026 Easy
More PYQs from KCET
- The mass defect of \( { }_{2}^{4} \mathrm{He} \) is \( 0.03 \mathrm{u} \). The binding energy per nucleon of helium (in \( \mathrm{MeV} \) ) isKCET 2017 Hard
- The statement that is NOT correct isKCET 2014 Easy
- Assume the graph of specific binding energy versus mass number is as shown in the figure. Using this graph, select the correct choice from the following.
KCET 2010 Medium - At \(500 \mathrm{~K}\), for a reversible reaction \(A_2(g)+B_2(g) \rightleftharpoons 2 A B(g)\) in a closed container, \(K_C=2 \times 10^{-5}\). In the presence of catalyst, the equilibrium is attaining 10 times faster. The equilibrium constant \(K_C\) in the presence of catalyst at the same temperature isKCET 2023 Easy
- What is the increasing order of acidic strength among the following?
(i) p-methoxy phenol
(ii) p-methyl phenol
(iii) p-nitro phenolKCET 2018 Hard - The resistance of \(0.01 \mathrm{~m} \mathrm{KCl}\) solution at \(298 \mathrm{~K}\) is \(1500 \Omega\). If the conductivity of \(0.01 \mathrm{~m} \mathrm{KCl}\) solution at \(298 \mathrm{~K}\) is \(0.1466 \times 10^{-3} \mathrm{~S} \mathrm{~cm}^{-1}\). The cell constant of the conductivity cell in \(\mathrm{cm}^{-1}\) isKCET 2021 Hard