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Which of the following statements is not correct? - Chemistry

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प्रश्न

Which of the following statements is not correct?

विकल्प

  • Copper liberates hydrogen from acids.

  • In its higher oxidation states, manganese forms stable compounds with oxygen and fluorine.

  • \[\ce{Mn^{3+}}\] and \[\ce{Co^{3+}}\] are oxidising agents in aqueous solution.

  • \[\ce{Ti^{2+}}\] and \[\ce{Cr^{2+}}\]  are reducing agents in aqueous solution.

MCQ
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उत्तर

Copper liberates hydrogen from acids.

Explanation:

Copper does not liberate hydrogen from acids.

\[\ce{Cu + 2H2SO4 -> CuSO4 + SO2 + 2H2O}\]

\[\ce{3Cu + 8HNO3 -> 3Cu (NO3)2 + 2NO + 4H2O}\]

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 8: The d-and f-Block Elements - Multiple Choice Questions (Type - I) [पृष्ठ १०८]

APPEARS IN

एनसीईआरटी एक्झांप्लर Chemistry [English] Class 12
अध्याय 8 The d-and f-Block Elements
Multiple Choice Questions (Type - I) | Q 17 | पृष्ठ १०८

संबंधित प्रश्न

Which of the following cations are coloured in aqueous solutions and why ?

Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)


In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?


In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?


To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.


Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:

Electronic configurations


Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.


How would you account for the following? 

Zr (Z = 40) and Hf (Z = 72) have almost identical radii.

 


Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
 in basic medium.


Electronic configuration of Mn2+ is ____________.


Ionisation enthalpies of Ce, Pr and Nd are higher than Th, Pa and U. Why?


EΘ of Cu is + 0.34V while that of Zn is – 0.76V. Explain.


Account for the following: 

In case of transition elements, ions of the same charge in a given series show progressive decrease in radius with increasing atomic number.


The element with atomic number 53 belongs to


Which of the following is non-metallic?


On adding NaOH, solution to the aqueous solution of K2CrO7 the colour of the solution changes from


Consider the following standard electrode potential values:

\[\ce{Sn^{2+}_{ (aq)} + 2e^- -> Sn_{(s)}}\]; E0 = −0.14 V

\[\ce{Fe^{3+}_{ (aq)} + e^- -> Fe^{2+}_{ (aq)}}\]; E0 = +0.77 V

What is the cell reaction and potential for the spontaneous reaction that occurs?


Write the number of unpaired electrons in Cr3+.
(Atomic number of Cr = 24)


The second ionization enthalpies of chromium and manganese are 1592 and 1509 kJ/mol respectively. Explain the lower value of Mn.


Give a reason for the following.

Some transition metals and their compounds get attracted towards the magnetic field.


For M2+/M and M3+/M2+systems, the EΘ values for some metals are as follows:

Cr2+/Cr −0.9 V
Mn2+/Mn −1.2 V
Fe2+/Fe −0.4 V
Cr3/Cr2+ −0.4 V
Mn3+/Mn2+ +1.5 V
Fe3+/Fe2+ +0.8 V

Use this data to comment upon:

The ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.


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