Description : (a) If the radius of the Br ion is 0.182 nm, how large a cation can fit in each of the tetrahedral hole. (b) AgI crystallizes in a cubic closed packed ZnS structure. What fraction of tetrahedral site ... Ag ion ? (c) At what temp. range, most of the metals becomes super conductors ?
Last Answer : (a) For a tetrahedron the limiting ratio is 0.225 – 0.414 For largest cation highest value 0.414 would be considered. r + / r– = 0.414 r + = 0.414 × 0.182 = 0.075 nm. (b) In FCC there are 8 tetrahedral voids. Out of this ½ is occupied by Ag cation. (c) 2 k – 5 k.
Description : The number of octahedral void(s) per atom present in a cubic close-packed structure is (1) 4 (2) 1 (3) 3 (4) 2
Last Answer : 1
Description : Diamond is harder than graphite because of – (1) difference in layers of atoms (2) tetrahedral structure of diamond (3) difference of crystalline structures (4) None of these
Last Answer : (1) difference in layers of atoms Explanation: Diamond is harder than graphite because diamond has a more complex structure. Diamond's structure is like many pentagons connected together, each pentagon ... together in some way. Graphite's structure is very loose, with its bonds forming layers.
Description : Diamond is harder than graphite because of : (1) difference in layers of atoms (2) tetrahedral structure of diamond (3) difference of crystalline structures (4) None of these
Last Answer : difference in layers of atoms
Description : The size of the tetrahedral void in the closest packing of atoms is __________ that of the octahedral void. (A) Equal to (B) Greater than (C) Less than (D) Either (A), (B) or (C); depends on the size of atom
Last Answer : (C) Less than
Description : There are one octahedral void and __________ tetrahedral void in the closest packing of atoms. (A) One (B) Two (C) Three (D) None of these
Last Answer : Option B
Description : What is the sign of Zinc Blend ?
Last Answer : Zinc Blend Signal ZnS
Description : Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure. (A) Hexagonal close, packed (hcp) (B) Face centred cubic (fcc) (C) Body centred cubic (bcc) (D) Simple cubic
Last Answer : (D) Simple cubic
Description : Phenol `underset("distillation")overset("Zinc")(rarr)(A)underset("conc."HNO_(3) "at 333K")overset("conc." HNO_(3))(rarr)(B)underset("NaOH")overset(Zn)
Last Answer : Phenol `underset("distillation")overset("Zinc")(rarr)(A)underset("conc."HNO_(3) "at 333K" ... -nitroaniline D. toluene, m-nitrobenzene and m-toulidine
Description : Plants take zinc in the form of (a) ZnSO4 (b) Zn++ (c) ZnO (d) Zn.
Last Answer : (b) Zn++
Description : The emf of a Deniell cell “Zn | Zn2+|| Cu2+| Cu” can be increased by (A) Decreasing the surface area of the electrodes (B) Increasing the concentration of zinc sulphate solution (C) Increasing the surface area of the electrodes (D) Increasing the concentration of copper sulphate solution
Last Answer : (D) Increasing the concentration of copper sulphate solution
Description : The obturating material of choice for primary teeth following complete pulpectomy is, A. Zn phosphate cement and formcresol combination paste B. Quick setting hydroxide cement C. Zinc oxide and eugenol cement D. Gutta-percha E. Polycarboxylate cement
Last Answer : C. Zinc oxide and eugenol cement
Description : Brass is an alloy of copper and zinc having the relative percentage (A) 60-70% Cu and 30-40% Zn (B) 50-60% Cu and 40-50% Zn (C) 40-50 % Cu and 60-50% Zn (D) 30-40 % Cu and 60-70% Zn
Last Answer : A) 60-70% Cu and 30-40% Zn
Description : Asseration: `SeCl_(4)`, does not havea tetrahedral structure. Reason: `Se` in `SeCl_(4)` has two lone pairs.
Last Answer : Asseration: `SeCl_(4)`, does not havea tetrahedral structure. Reason: `Se` in `SeCl_(4)` has two lone pairs.
Description : Compound having tetrahedral structure is ______. (1) C2H4 (2) C2H2 (3) CH4 (4) None of these
Last Answer : (3) CH4 Explanation: Methane is a tetrahedral molecule with four equivalent C-H bonds. Its electronic structure is described by four bonding molecular orbital resulting from the overlap of the valence orbitals on C and H.
Description : The structure of an ammonia molecule can best be described as: w) linear x) tetrahedral y) pyramidal z) triagonal planar
Last Answer : ANSWER: Y -- PYRAMIDAL
Description : Out of `Cu_(2)S,HgS,Ag_(2)S` and ZnS roasting will convert the mineral in to metal case of
Last Answer : Out of `Cu_(2)S,HgS,Ag_(2)S` and ZnS roasting will convert the mineral in to metal case of A. `Cu_(2)S,Zns` B. Hgs,ZnS C. `Cu_(2)S,Ag_(2)S` D. HgS
Description : Should I buy a diamond or cubic zirconium engagement ring?
Last Answer : if you can afford the diamond then go for it because when shopping for engagement rings cost is actually one of the biggest factors and diamond is more expensive and also many people thinks ... then diamonds is the best choice as zirconia captures light differently which makes them shines less.
Description : When ZnS and PbS minearls are present together, then NaCN is added to separate them in the froth floatation process as a depressant, because :
Last Answer : When ZnS and PbS minearls are present together, then NaCN is added to separate them in the froth ... ]` D. They cannot be separated by adding NaCN
Description : `NaCN` is sometimes added in the froth flotation process as a depressant when `ZnS` and `PbS` minerals are expected because `:`
Last Answer : `NaCN` is sometimes added in the froth flotation process as a depressant when `ZnS` and `PbS` ... D. Sillccious impurities settle down on the bottom.
Last Answer : When ZnS and PbS minearls are present together, then NaCN is added to separate them in the froth floatation process as ... _(4)]` D. both (1) and (2)
Description : Which of the following is used for the seperation of ZnS and PbS during the froth flotation process?
Last Answer : Which of the following is used for the seperation of ZnS and PbS during the froth flotation process? A. KCl B. KCN C. `NH_(4)NO_(3)` D. None of these
Description : In sulphation roasting of `ZnS` products are
Last Answer : In sulphation roasting of `ZnS` products are A. `ZnO+ZnSO_(4)+SO_(2)` B. `ZnCl_(2)` C. `ZnO+SO_(2)` D. `Zn+SO_(2)`
Description : In the following reaction: `ZnS+O_(2)overset(Delta)rarrA+ZnO` `4HCl+O_(2)overset(CuCl_(2))rarrB+2H_(2)O` `A+B overset(hv)rarrC` Then A, B and C are:
Last Answer : In the following reaction: `ZnS+O_(2)overset(Delta)rarrA+ZnO` `4HCl+O_(2)overset(CuCl_(2))rarrB+2H_(2)O` ` ... SOCl_(2)` D. `SO_(3),HClO_(3),HClO_(4)`
Description : What is the oxidation half reaction for mgs plus zncl2aq mgcl2aq plus zns?
Last Answer : What is the answer ?
Description : How does NaCN act as a depressant in preventing ZnS from forming the froth ?
Last Answer : Ans. NaCN forms a layer of zinc complex, Na2 [Zn (CN)4 ] on the surface of ZnS and thereby prevents it from the formation of froth.
Description : Lithophane is (A) Explosive (B) White lead (C) Filter aid (D) ZnS (white pigment)
Last Answer : (D) ZnS (white pigment)
Description : Which of the following substances is classified as amorphous? w) glass x) Zinc y) diamond z) sodium chloride
Last Answer : ANSWER: W -- GLASS
Description : In the event of cabin depressurization, the actions of the pilot will be to: a. Immediately commence a diversion to a suitable alternate b. Increase engine power to provide additional ... a descent to an altitude where the supplemental oxygen supply is sufficient for all crew and passengers
Last Answer : d. Commence a descent to an altitude where the supplemental oxygen supply is sufficient for all crew and passengers
Description : One method of troubleshooting digital circuits in a console is to ___________. A. supply alternate logic levels at the input(s) and test for change of state conditions at the output B. ground all ... output D. vary each input smoothly from 0-10 volts and test for similar variance at the output
Last Answer : Answer: A
Description : Materials having __________ lattice structure are usually most ductile. (A) FCC (B) BCC (C) HCP (D) Cubic
Last Answer : (A) FCC
Description : Pick out the wrong statement. (A) Metal/alloys having hexagonal crystal lattice structure are less malleable than those having cubic crystal lattice structure (B) Metal/alloys having body centred cubic ... D) Both ferritic & austenitic stainless steel has a face centred cubic (fcc) crystal structure
Last Answer : (C) Tungsten has a body centred cubic (bcc) crystal lattice structure
Description : Nickel as a material of construction (A) Is used as an alloying element for both ferrous & non-ferrous alloys (B) Is paramagnetic below 415° C (its Curie temperature) (C) Diamagnetic (D) Has a body centred cubic (bcc) crystal lattice structure
Last Answer : (A) Is used as an alloying element for both ferrous & non-ferrous alloys
Description : Most of the common metals have __________ crystal structure. (A) Cubic (B) Hexagonal (C) Orthorhombic (D) None of these
Last Answer : (A) Cubic
Description : The crystal structure of most of the common metals is (A) Orthorhombic (B) Cubic (C) Hexagonal (D) None of these
Last Answer : (B) Cubic
Description : The co-ordination number in simple cubic structure is (A) 4 (B) 6 (C) 8 (D) 12
Last Answer : (B) 6
Description : Mild steel has __________ crystal lattice structure. (A) Face centred cubic (fcc) (B) Body centred cubic (bcc) (C) Orthorhombic (D) Cubic
Last Answer : (B) Body centred cubic (bcc)
Description : How many neighboring atoms are in contact with eac atom in a monatomic body-centered cubic structure. w) 4 x) 6 y) 8 z) 12
Last Answer : ANSWER: Y -- 8
Description : The co-ordination number of a simple cubic structure is
Last Answer : The co-ordination number of a simple cubic structure is 6.
Description : Why are low spin tetrahedral complexes not formed? -Chemistry
Last Answer : Law spin tetrahedral complexes are rarely observed because orbital splitting energies for tetrahedral complexes are sufficiently large for forcing pairing.
Description : The species having tetrahedral shape is
Last Answer : The species having tetrahedral shape is A. `[PdCl_(4)]^(2-)` B. `[Ni(CN)_(4)]^(2-)` C. `[Pd(CN)_(4)]^(2-)` D. `[Ni(Cl)_(4)]^(2-)`
Description : The magnitude of crystal field stabilisation energy (CFSE of `Delta_(1)`) in tetrahedral complexes is considerably less than that in the octahderal fi
Last Answer : The magnitude of crystal field stabilisation energy (CFSE of `Delta_(1)`) in tetrahedral complexes is ... Both point (A) and (B) are wrong.
Description : A coordination complex of type `MX_(2)Y_(2)`[M=metal ion, X,Y=monodentata ligands ], can have either a tetrahedral of a square planar geometry. The ma
Last Answer : A coordination complex of type `MX_(2)Y_(2)`[M=metal ion, X,Y=monodentata ligands ], can have either a tetrahedral ... 2 and 1 C. 1 and 3 D. 3 and 2
Description : The species having tetrahedral shape is :
Last Answer : The species having tetrahedral shape is : A. `[PdCl_(4)]^(2-)` B. `[Ni(CN)_(4)]^(2-)` C. `[Pd(CN)_(4)]^(2-)` D. `[NiCl_(4)]^(2-)`
Description : All the following complexes show decrease in their weights when placed in a magnetic balance then the group of complexes having tetrahedral geometry i
Last Answer : All the following complexes show decrease in their weights when placed in a magnetic balance then the group of ... III C. I,III,IV D. none of these
Description : Which of the following molecules is not tetrahedral ?
Last Answer : Which of the following molecules is not tetrahedral ? A. `[Pt(en)_(2)]^(2+)` B. `[Ni(CO)_(4)]` C. `[Zn(NH_(3))_(4)]^(2+)` D. `[NiCl_(4)]^(2-)`
Description : The crystl field splitting energy for octahedral complex `(Delta_(0))` and that for tetrahedral complex `(Delta_(1))` rae related as :
Last Answer : The crystl field splitting energy for octahedral complex `(Delta_(0))` and that for tetrahedral complex `(Delta_(1) ... ` D. `Deltat=(9)/(4)Delta_(0)`
Description : Assertion: Bond angle at oxygen in ethehers is greater than ideal tetrahedral angle Reason: Stearic hindrance between alkyl groups increase bond angle
Last Answer : Assertion: Bond angle at oxygen in ethehers is greater than ideal tetrahedral angle Reason: Stearic ... D. Assertion is false, Reason is true