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प्रश्न
Assertion (A): Cu cannot liberate hydrogen from acids.
Reason (R): Because it has positive electrode potential.
Assertion (A): Cu cannot liberate H2 on reaction with dilute mineral acids.
Reason (R): Cu has positive electrode potential.
विकल्प
Both assertion and reason are true, and reason is the correct explanation of the assertion.
Both assertion and reason are true but reason is not the correct explanation of assertion.
Assertion is not true but reason is true.
Both assertion and reason are false.
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उत्तर
Both assertion and reason are true, and reason is the correct explanation of the assertion.
Explanation:
Copper has a positive electrode potential, so it is less reactive than hydrogen and cannot displace H+ ions from dilute acids to release hydrogen gas.
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संबंधित प्रश्न
What are the transition elements? Write two characteristics of the transition elements.
What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of its atom?
3d3
What are inner transition elements?
NF3 is possible, but NF5 is not. Why?
Give reasons Iron has the higher enthalpy of atomization than that of copper.
Explain why transition elements form alloys.
Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)
Transition metals with highest melting point is ____________.
Which of the following statements is not correct?
Highest oxidation state of manganese in fluoride is \[\ce{+4 (MnF4)}\] but highest oxidation state in oxides is \[\ce{+7 (Mn2O7)}\] because ______.
Why is \[\ce{HCl}\] not used to make the medium acidic in oxidation reactions of \[\ce{KMnO4}\] in acidic medium?
Why does copper not replace hydrogen from acids?
Match the solutions given in Column I and the colours given in Column II.
| Column I (Aqueous solution of salt) |
Column II (Colour) |
| (i) \[\ce{FeSO2.7H2O}\] | (a) Green |
| (ii) \[\ce{NiCl2.4H2O}\] | (b) Light pink |
| (iii) \[\ce{MnCl2.4H2O}\] | (c) Blue |
| (iv) \[\ce{CoC12,6H2O}\] | (d) Pale green |
| (v) \[\ce{Cu2 Cl2}\] | (e) Pink |
| (f) Colourless |
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
A complex in which dsp2 hybridisation takes place is ______.
Which of the following ions has the maximum magnetic moment?
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
The given graph shows the trends in melting points of transition metals:
Explain the reason why Cr has the highest melting point and manganese (Mn) has a lower melting point.
Explain the use of different transition metals as catalysts.
Give a reason for the following:
Zinc, cadmium and mercury are considered as d-block elements but not regarded as transition elements.
