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प्रश्न
An antifriction alloy made up of antimony with tin and copper, which is extensively used in machine bearings is called _______.
(A) Duralumin
(B) Babbitt metal
(C) Spiegeleisen
(D) Amalgam
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उत्तर
(B) Babbitt metal
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संबंधित प्रश्न
Why is Sc3+ colourless while Ti3+ coloured? (Atomic number Sc = 21, Ti =22)
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)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element has the highest m.p?
What are the transition elements? Write two characteristics of the transition elements.
How would you account for the following : Transition metals form coloured compounds
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
What are the characteristics of the transition elements and why are they called transition elements?
Use Hund’s rule to derive the electronic configuration of Ce3+ ion and calculate its magnetic moment on the basis of ‘spin-only’ formula.
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
Write down the number of 3d electrons in the following ion:
Cu2+
Indicate how would you expect the five 3d orbitals to be occupied for this hydrated ion (octahedral).
Why do transition metal ions possess a great tendency to form complexes?
Explain why transition metals and their compounds act as a catalyst.
Although Zirconium belongs to 4d transition series and Hafnium to 5d transition series even then they show similar physical and chemical properties because ______.
Why is \[\ce{HCl}\] not used to make the medium acidic in oxidation reactions of \[\ce{KMnO4}\] in acidic medium?
Transition elements form binary compounds with halogens. Which of the following elements will form \[\ce{MF3}\] type compounds?
(i) \[\ce{Cr}\]
(ii) \[\ce{Co}\]
(iii) \[\ce{Cu}\]
(iv) \[\ce{Ni}\]
The halides of transition elements become more covalent with increasing oxidation state of the metal. Why?
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d orbital but reverse happens during the ionisation of the atom. Explain why?
Assertion: \[\ce{Cu^2+}\] iodide is not known.
Reason: \[\ce{Cu^2+}\] oxidises \[\ce{I^-}\] to iodine.
Assertion: Separation of \[\ce{Zr}\] and \[\ce{Hf}\] is difficult.
Reason: Because \[\ce{Zr}\] and \[\ce{Hf}\] lie in the same group of the periodic table.
Assertion (A): Cu cannot liberate hydrogen from acids.
Reason (R): Because it has positive electrode potential.
Identify the metal and justify your answer.
\[\ce{MO3F}\]
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
(activation energy, Threshold energy, increased, lowered, partially, full, d-d transition, Benzoic acid, benzaldehyde)
Only those transition metal ions will be coloured which have ______ filled d-orbitals facilitating ______.
The element with atomic number 53 belongs to
The spin magnetic moment of cobalt in the compound Hg [Co(SCN)4] is:-
The complex showing a spin-span magnetic moment of 2.82 B.M. is :-
The value of Δ0 for \[\ce{RhCl^{3-}6}\] is 243 KJ/mol which wavelength of light will promote an electron from. The colour of the complex is ______.
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.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with H2S.
Decide which of the following atomic numbers are the atomic numbers of the inner transition elements:
29, 59, 74, 95, 102, 104
