Number of three–centre two–electron (3c–2e) bonds present in diborane is
Which one of the following order of the carbonates is correct for their decomposition temperature:
The common feature (s) of Rb+, Kr and Br– is /are that they:
The characteristics of the blue solution of solution of sodium in liquid ammonia is/are:
Do you expect the minimum energy necessary to eject a 3s electron from phosphorus in a photoelectron spectroscopy experiment for the process.
[Ne] 3s23p3 → [Ne] 3s13p3 + e- ,
Be larger than, smaller than, or the same as the 4th io nization energy (IE4) of phosphorus:
Due to better guarding of s electrons by p if we directly remove an s electron without removing the p electrons, it would take more energy had we removed all outer electrons before.
Hence A is correct.
Which of the following will be strongest acid in pure liquid HF:
Correct Answer :- b
Explanation : Fluoroantimonic acid is the strongest superacid based on the measured value of its Hammett acidity function (H0), which has been determined for different ratios of HF:SbF5. While the H0 of pure HF is −15, addition of just 1 mol % of SbF5 lowers it to around −20.
What is the nature of silicon–oxygen bonds in silica(SiO2):
The melting point of lithium metal is 454 K, and that of sodium is 371 K. Which is the following statements can explain this difference in their melt ing points:
(I) Metallic bonding in lithium is stronger than metallic bonding in sodium.
(II) The delocalized electrons are more strongly attracted to the metal cation of lithium.
(III) The lithium cations have a greater charge density than sodium cation.
(IV) Li+ cations are smaller than Na+ cations.
Although both NF3 and NCl3 are covalent, NCl3 undergoes hydrolysis whereas NF3 does not because:
The Lewis acidity of BF3 is less than BCl3 even though fluorine is more electronegative than chlorine. It is due to:
Pyroenes are a class of silicate minerals, which exhibit a polymeric chain structure, as shown below:
Its simplest repeat unit is
In the following reactions:
The reagent/conditions X and Y are:
Hexachlorophosphazene gives Sn2 reaction with NaF and heating hexachlorophosphazene to 250 °C induces polymerization.
Among the following, the group of molecules that undergoes rapid hydrolysis is:
The reaction of so lid XeF2 with AsF5 in 1:1 ratio affords:
For Et2AlX (X = PPh2–, Ph–, Cl– –and H–), the tendency towards dimeric structure fo llows the order:
Na2HPO4 and NaH2PO4 on heating at high temperature produce a chain sodium pentaphosphate quantitatively.
Q.
The ideal molar ratio of Na2HPO4 to NaH2PO4 is:
2Na2HPo4 + 3NaH2Po4 --->Na7P5o16
Na2HPO4 and NaH2PO4 on heating at high temperature produce a chain sodium pentaphosphate quantitatively.
Q.
The total charge on pentaphosphate anion is:
Correct Answer :- a
Explanation : Sodium tripolyphosphate is produced by heating a stoichiometric mixture of disodium phosphate, Na2HPO4, and monosodium phosphate, NaH2PO4, under carefully controlled conditions.
2Na2HPO4 + NaH2PO4 → Na5P3O10 + 2 H2O
STPP is a colourless salt, which exists both in anhydrous form and as the hexahydrate. The anion can be described as the pentanionic chain [O3POP(O)2OPO3]5-
Among the following substituted silanes, the one that gives cross–linked silicone polymer upon hydrolysis is:
Among the following donors, the one that forms most stable adduct with the Lewis acid B(CH3)3 is:
The IUPAC nomenclature on Na[PCl6] is:
If a mixture of NaCl, conc. H2SO4 and K2Cr2O7 is heated in a dry test tube, a red vapour (P) is formed. This vapour (P) dissolves in aqueous NaOH to form a yellow solution, which upon treatment with AgNO3 forms a red solid (Q). P and Q are, respectively:
Heating a mixture of ammonium chloride and sodium tetrahydridoborate gives one liquid product(X), along with other products under ambient conditions.
NH4Cl + NaBH4 ------------> X + H2 + NaCl
Q.
Compound X is:
NH4Cl + NaBH4 ------------> B3N3H6 + H2 + NaCl
Heating a mixture of ammonium chloride and sodium tetrahydridoborate gives one liquid product(X), along with other products under ambient conditions.
NH4Cl + NaBH4 ------------> X + H2 + NaCl
Q.
Compound X is an example of:
An example of nido–borane from the following is:
The number of S–S bonds in H2S5O6 is
The ease of formation of the adduct, NH3 · BX3 (where X = F, Cl, Br) follows the order:
Ammonolysis of S2Cl2 in an inert solvent gives:
Using Wade’s rule predict the structure of B5H9:
Which among the following is a “superoxide”:
Aqua regia is a powerful oxidizing agent because it contains:
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