Why are pentahalides more covalent than trihalides?
The group 15 elements (nitrogen, phosphorus,arsenic,antimony and bismuth) when reacted with halogen atom ,tend to form halides. The halides formed are of two types:
1) Trihalides (MX3)
2) Pentahalides (MX5) where M -15TH group element X- halogen atom
The trihalides are formed by all the elements of group 15 while pentahalides are formed by all the elements except nitrogen because there is absence of vacant d- orbital in its outermost shell.
The oxidation state of +5 in pentahalides is more as compared to +3 oxidation state in trihalides. Due to the higher positive oxidation state of central atom in pentahalide state, these atoms will have larger polarizing power than the halogen atom attached to them. The central atom in pentahalide state will tend to polarize more the halide ion to which it is attached.
But In case of trihalides due to +3 oxidation state the central atom will polarize the halogen atom to a lesser extent as compared to pentahalide state. Therefore, more the polarization, larger will be the covalent character of the bond.
Hence due larger polarization of bond in pentahalide state as compared to trihalide state, the pentahalides are more covalent than trihalides.
Why is helium used in diving apparatus?
Give the formula and describe the structure of a noble gas species which is isostructural with:
(i) ICl-4
(ii) IBr-2
(iii) BrO-3
Why is H2O a liquid and H2S a gas?
How is O3 estimated quantitatively?
What happens when sulphur dioxide is passed through an aqueous solution of Fe(III) salt?
Why is BiH3 the strongest reducing agent amongst all the hydrides of Group 15 elements?
Why are halogens strong oxidising agents?
Arrange the following in the order of property indicated for each set:
(i) F2, Cl2, Br2, I2- increasing bond dissociation enthalpy.
(ii) HF, HCl, HBr, HI - increasing acid strength.
(iii) NH3, PH3, AsH3, SbH3, BiH3- increasing base strength.
Comment on the nature of two S-O bonds formed in SO2 molecule. Are the two S-O bonds in this molecule equal?
Mention the conditions required to maximise the yield of ammonia.
For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.
Write the formulas for the following coordination compounds:
(i) Tetraamminediaquacobalt (III) chloride
(ii) Potassium tetracyanonickelate(II)
(iii) Tris(ethane-1,2-diamine) chromium(III) chloride
(iv) Amminebromidochloridonitrito-N-platinate(II)
(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate
(vi) Iron(III) hexacyanoferrate(II)
(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
Why are solids rigid?
Write any two characteristics of Chemisorption.
Write the structures of the following compounds.
(i) α-Methoxypropionaldehyde
(ii) 3-Hydroxybutanal
(iii) 2-Hydroxycyclopentane carbaldehyde
(iv) 4-Oxopentanal
(v) Di-sec-butyl ketone
(vi) 4-Fluoroacetophenone
Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?
Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?
Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
Write structures of the following compounds:
(i) 2-Chloro-3-methylpentane
(ii) 1-Chloro-4-ethylcyclohexane
(iii) 4-tert. Butyl-3-iodoheptane
(iv) 1,4-Dibromobut-2-ene
(v) 1-Bromo-4-sec. butyl-2-methylbenzene
The decomposition of NH3on platinum surface is zero order reaction. What are the rates of production of N2and H2if k = 2.5 x 10-4mol-1L s-1?
If NaCl is doped with 10-3mol % of SrCl2, what is the concentration of cation vacancies?
Why do gases always tend to be less soluble in liquids as the temperature is raised?
Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure of a mixture of 26.0 g of heptane and 35 g of octane?
Explain the difference between Buna-N and Buna-S.
Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it.
Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?
The experimental data for decomposition of N2O5
[2N2O5 → 4NO2 + O2]
in gas phase at 318K are given below:
t/s | 0 | 400 | 800 | 1200 | 1600 | 2000 | 2400 | 2800 | 3200 |
102 × [N2O5] mol L-1 | 1.63 | 1.36 | 1.14 | 0.93 | 0.78 | 0.64 | 0.53 | 0.43 | 0.35 |
(i) Plot [N2O5] against t.
(ii) Find the half-life period for the reaction.
(iii) Draw a graph between log[N2O5] and t.
(iv) What is the rate law ?
(v) Calculate the rate constant.
(vi) Calculate the half-life period from k and compare it with (ii).
Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.
Write the structures of products of the following reactions;
(i)
(ii)
(iii)
(iv)
More the polarization more the covalent. I couldn't understand this line. If there is more polarization it could be more ionic. Am i correct.please clarify me
Supb
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