12th chemistry Chapter 3-Chemical Kinetics
Welcome, 12th chemistry exam Important question based on CBSE board curriculum and corresponding to the recent 12 class Chemistry syllabus in text questions.
By rehearsing these Class 12 significant inquiries, understudies will actually want to rapidly survey every one of the thoughts shrouded in the part and plan for the Class 12 Yearly assessments as well as other selection tests like NEET and JEE.
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Check our 12th Chemistry exam solution of chapter 2 click here.
Can absolute electrode potential of an electrode be measured?(Chemistry book)
the absolute potential of an electrode can not be measured because the half-cell containing a single electrode cannot work on its own. It can work only in combination with another half cell.
What does the negative sign in the expression E0Zn2+ /Zn = – 0.76 V means?(Chemistry book)
It implies that Zn is more reactive than hydrogen or it is a stronger reducing agent. In a cell containing zinc electrode and standard hydrogen electrode present in two half cells, zinc will be oxidised to Zn2+ ions while H+ ions will get reduced to hydrogen.
Aqueous copper sulphate solution and aqueous silver nitrate solution are electrolysed by 1 ampere current for 10 minutes in separate electrolytic cells. Will the mass of copper and silver deposited on the cathode be same or different ? Explain your answer.(Chemistry book)
The mass of copper and silver deposited on the cathode in the two electrolytic cells will not be the same.
According to second law of Electrolysis.
(Mass of Cu deposited /mass of Ag deposited) = (equivalent mass of Cu/equivalent mass of Ag)
= 31.75/ 108.
Depict the galvanic cell in which the cell reaction is : Cu + 2Ag+ → 2Ag + Cu2+.(Chemistry book)
In the cell reaction: Cu + 2Ag+ → 2Ag + Cu2+
At anode : Cu → Cu2+ + 2e
At Cathode : 2 Ag+ + 2e → 2Ag
The representation of cell = Cu(s) | Cu2+(aq) || Ag+(aq) | Ag (s)
Value of standard electrode potential for the oxidation of Cl– ions is more positive than that of water, even then in the electrolysis of aqueous sodium chloride, why are Cl– ions oxidised at anode instead of water ?(Chemistry book)
The oxidation reactions taking place at anode is:
2Cl– (aq) → Cl2 (g) + 2e– E0(oxid) = -1.36 V
2H2O (l) → O2 (g) + 4H+ (aq) + 4e– E0(oxid) = -1.23 V
Due to the overvoltage of oxygen (O₂), its liberation is kinetically slower than that of CI ions. Therefore, Cl ions are oxidised to Cl₂ gas.
Some example for sum:
What is electrode potential ?(Chemistry book)
Because of the transfer of charged species across the interface, electrode potential appears at the interface between an electrode and an electrolyte.
Solutions of two electrolytes ‘A’ and ‘B’ are diluted. The Λm of ‘B’ increases 1.5 times while that of A increases 25 times. Which of the two is a strong electrolyte? Justify your answer.(Chemistry book)
Solution: As the electrolyte is diluted, the interionic attractive force is primarily reduced, leading to an increase in Γm. When a strong electrolyte is present, it completely dissociates in solution, causing Γm to slightly increase with dilution. Conversely, there is very little ionization of the electrolyte weak. Its ionization or dissociation increases considerably with dilution. For this reason, at dilution, Γm for weak electrolyte is more extensive.
Why is alternating current used for measuring resistance of an electrolytic solution?(Chemistry book)
Since direct current will cause the electrolyte to electrolyze, alternate current is employed to measure the resistance of an electrolytic solution. The ions’ concentration in the solution will alter as a result.
How will the pH of brine (NaCl solution) be affected when it is electrolysed?(Chemistry book)
Since direct current will cause the electrolyte to electrolyze, alternate current is employed to measure the resistance of an electrolytic solution. The ions’ concentration in the solution will alter as a result.
Which reference electrode is used to measure the electrode potential of other electrodes ?(Chemistry book)
The standard hydrogen electrode (SHE) serves as a reference electrode for measuring the potential of other electrodes. It is assumed that its electrode potential is zero. The standard electrode potential (E) of any electrode is the electrode potential measured with respect to a standard hydrogen electrode.
What advantage do the fuel cells have over primary and secondary batteries?(Chemistry book)
Reactants are contained in limited quantities in primary batteries or cells, which are discharged when the reactants are used up. It is possible to recharge secondary batteries or cells, but it is a time-consuming procedure. Fuel cells function nonstop as long as reactants, or fuel, are available.
Write the cell reaction of a lead storage battery when it is discharged. How does the density of the electrolyte change when the battery is discharged?(Chemistry book)
The cell reaction of a lead storage battery when it is discharged, may be given as:
Pb(s) + 4H+(aq) + 2SO42- (aq) → PbO₂(s) + 2PbSO4 (s) + 2H₂O(l)
Density of the electrolyte i.e. conc.H2SO4 solution decreases because of the dilution of electrolyte taking place since water is formed as one of the products.
Why on dilution the Λm of CH3COOH increases drastically, while that of CH3COONa increases gradually?(Chemistry book)
CH3COOH is a weak electrolyte that is only partially dissociated. With dilution, the degree of dissociation increases, releasing more ions into solution. As a result, the m of CH3COOH increases dramatically. CH3COONa, on the other hand, is a strong electrolyte that is almost completely dissociated in aqueous solution. Only the interionic forces of attraction increase with dilution, resulting in a small increase in the value of m.
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