Description : Which of the statements is not true? (1) K2Cr2O7 solution becomes yellow on increasing the pH beyond 7 (2) On passing H2 S through acidified K2Cr2O7 solution, a milky colour is observed (3) Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis (4) K2Cr2O7 solution in acidic medium is orange
Last Answer : Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis
Description : Explain the following , giving reason . (a) Transition metal and many of their compounds show paramagnetic behavior (b) The enthalpy of atomisation of the transition metal is high . (c) The Transition metal generally form coloured compounds .
Last Answer : Ans(a) It is due to unpaired electrons . (b) It is due to strong metallic bond and additional Covalent bonds due to presence of unpaired electron in d- orbitals (c) It is due to presence of unpaired electrons ,they undergo d-d transition .
Description : Why are transition metals and there compounds generally coloured ?
Last Answer : Ans It is due to present of unpaired electrons in transition metals and their ions , that is why they absorbed light from visible region and undergoes d-d transition and radiate complementary colour .
Description : What is an lanthanoid contraction ? What is its cause ? Give its consequences .
Last Answer : Ans The decrease in atomic and ionic size with increase in atomic no. in lanthanoid series is called lanthanoid contraction . The cause of lanthanoid contraction is poor shielding effect of d and f ... is close resemblance between elements of 4 d and 5 d transition series . due to similar ionic
Description : Why are Ti+2 and other transition metals and their ions paramagnetic ?
Last Answer : Ans: These ions have unpaired electrons in d- subshell.
Description : Why do transition metals have higher I.E than s –block elements ?
Last Answer : Ans: It is due to smaller atomic size than s-block elements , effective nuclear charge is more , terefore I.E is high.
Description : Why are lanthanoid colored and paramagnetic L
Last Answer : Ans It is due to presence of unpaired electrons, they are paramagnetic and they absorb light From visible region and undergoes f-f transition and radiate complementary colour .
Description : Why Mn+2 is more stable than Mn+3 but Fe +3 is more stable than Fe+2 ?
Last Answer : Ans Mn+2 has half filled d- orbital ,therefore it is more stable than Mn+3 Fe+3 has half filled d- orbital, therefore it is more stable than Fe +2 .
Description : Why are transition metal fluorides are ionic in nature where as chlorides and bromides are covalent in nature .
Last Answer : Ans - It is because of fluorine is most electronegative where as Cl and Br are less electro negative . Greater the difference in electro negativity more will be ionic character .
Description : Why is Cu+1 diamagnetic and Cu +2 paramagnetic ?
Last Answer : It is because Cu+ does not have unpaired electrons where as Cu+2 has unpaired electrons in d-sub cell .
Description : Why do Zr and Hf show similar properties ?
Last Answer : Ans It is due to similar ionic size which due to lanthanide contraction .
Description : Why are Cr+ , Ag+ & Sc+3 Colour less ?
Last Answer : Ans It is because they do not have unpaired electrons ,therefore can not under goes d-d transition .
Description : Why does V2O5 acts as catalyst ?
Last Answer : Ans : It is because V shows variable O.S .
Description : Why Ce+3 Can be easily Oxidised to Ce+4 ?
Last Answer : Ans : It is because Ce+4 has stable electronic configuration .
Description : Why do transition metals have high enthalpy of atomization ?
Last Answer : Ans : it is due to strong metallic bonds and additional covalent bonds
Description : What is the highest oxidation state shown by Cr. (24) , Mn(25) ?
Last Answer : Ans: Cr. Shows (+6) and Mn Shows (+7) Oxidation state .
Description : Why are Zn , Cd , Hg are not regarded as transition metals ?
Last Answer : Ans: It is because neither they nor their ions have incompletely filled d- orbitals .
Description : What are d Block Elements ?
Last Answer : Ans: Those elements in which d-orbital are progressively filled up are known as d-orbital.
Description : Application of d- & f- block elements
Last Answer : Application of d- & f- block elements:- 1. Iron and steel used in construction,as catalyst in Haber's process 2. CrO2 is used in magnetic tapes 3. Ni is in hydrogenation 4. W ( ... in contact process 9. Titanium is in nuclear reactions. 10. PdCl2 is in Wacker's process.
Description : Aniline undergoes oxidation with Na2Cr2O7/H2SO4 to give (a) Schiff's base (b) p-Benzoquinone (c) Phenol (d) Benzoic acid
Last Answer : p-Benzoquinone
Description : Naphthalene undergoes oxidation with Na2Cr2O7 / H2SO4 to form (a) Phthalic acid (b) Phenylacetic acid (c) Tetralin (d) Benzoic acid
Last Answer : Phthalic acid
Description : By which of the following methods can CH3CONH2 be converted to CH3CN? (a) Oxidize with Na2Cr2O7/H+ (b) Heat with concentrated sulfuric acid (c) Heat to 200°C (d) Warm with P2O5
Last Answer : Warm with P2O5
Description : Oxidation of acetaldehyde with Na2Cr2O7/H+ gives (a) Ethylene glycol (b) Acetic acid (c) Ethanol (d) Acetone
Last Answer : Acetic acid
Description : Isopropyl alcohol can be converted to acetone by treatment with (a) HCl/ZnCl2 (b) Na2Cr2O7/H2SO4 (c) NaOH (d) LiAlH4
Last Answer : Na2Cr2O7/H2SO4
Description : Oxidation of cumene with acidic K2Cr2O7 gives (a) Phenylacetic acid (b) Benzaldehyde (c) Benzyl alcohol (d) Benzoic acid
Last Answer : Benzoic acid
Description : Which of the following reagents can be used to oxidize 1° alcohols to aldehydes? (a) KMnO4 (b) MnO2 (c) K2Cr2O7 (d) PCC
Last Answer : PCC
Description : Oxidation of a secondary alcohol with K2Cr2O7/H+ produces (a) a carboxylic acid (b) a ketone (c) an aldehyde (d) an ester
Last Answer : a ketone
Description : Collin’s Reagent is? a. K2Cr2O7/H2SO4 b. PCC/CH2Cl2 c. PDC/DCM d. CrO3/pyridine
Last Answer : d. CrO3/pyridine
Description : To convert volumetric analysis to gravimetric analysis, the relative volume of each constituent of the flue gases is (a) divided by its molecular weight (b) multiplied by its molecular weight (c) ... by its density (d) multiplied by its specific weight (e) divided by its specific weight.
Last Answer : Answer : b
Description : Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the (A) Mass transfer co-efficient (B) Thermal diffusivity (C) Kinematic viscosity (D) Volumetric diffusivity
Last Answer : (A) Mass transfer co-efficient
Description : iesel engine has less reserve torque then spark ignition because ∙ Torque-speed curve is governed by volumetric efficiency of fuel pump and engine cylinder ∙ Torque is a function of thermal efficiency ∙ Diesel engine has generally low speed engine ∙ None of the above
Last Answer : ∙ Torque is a function of thermal efficiency
Description : Is K2Cr2O7 ionic or molecular?
Last Answer : Need answer
Description : For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of A. H2SO4 B. HNO3 C. HCl D. None of these
Last Answer : ANS: A
Description : . Glass reacts with (A) H2SO3 (B) HF (C) HNO3 (D) K2Cr2O7
Last Answer : (B) HF
Description : Tip of the match stick contains a mixture of (A) K + S (B) K + S + K2Cr2O7 (C) S + K2Cr2O7 + White P (D) None of these
Last Answer : (C) S + K2Cr2O7 + White P
Description : Pick out the wrong statement. (A) Cumulative analysis for determining surface area is preferred over differential analysis, because of the assumption that "all particles in a simple fraction equal in size" is ... throwing of the balls through the air to the toe of the heap is called 'cataracting'
Last Answer : (C) Capacity of crusher in choke feeding is increased
Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers
Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres
Description : Convex weld is generally preferred over normal weld. a) True b) False
Last Answer : b) False
Description : Define volumetric strain. Also give the relation between lateral strain to and Poisson’s ratio.
Last Answer : Volumetric strain: Volumetric strain is defined as the ratio of change in volume to original volume.
Description : 221 For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is A. Cast iron sewers B. Cement concrete sewers C. Glazed bricks sewers D. Stone ware sewers
Last Answer : ANS: C
Description : Pumping of a corrosive liquid is generally preferred to be done by a __________ pump, as it can be made of a variety of materials including plastics. (A) Piston (B) Gear (C) Positive displacement (D) Sump
Last Answer : (B) Gear
Description : Cast iron pipes are generally preferred to, because (A) Of moderate cost (B) Of ease to join (C) Of longer life (D) All the above
Last Answer : (D) All the above
Description : A circular gravity aqueduct is not generally preferred to because of (A) Its maximum hydraulic mean depth (B) Maximum area per unit of wetted perimeter (C) Minimum cost of construction (D) Its proper support on the ground
Last Answer : (D) Its proper support on the ground
Description : True meridians are generally preferred to magnetic meridians because (A) These converge to a point (B) These change due to change in time (C) These remain constant (D) None of these
Last Answer : (C) These remain constant
Description : Subtense tacheometry is generally preferred to if ground is (A) Flat (B) Undulating (C) Mountainous (D) Deserts
Last Answer : (B) Undulating
Description : The method generally preferred to for contouring an undulating area, is (A) Chain surveying (B) Plane table surveying (C) Tacheometrical surveying (D) Compass surveying
Last Answer : (C) Tacheometrical surveying
Description : In tacheometrical observations, vertical staff holding is generally preferred to normal staffing, due to (A) Ease of reduction of observations (B) Facility of holding (C) Minimum effect of careless holding on the result (D) None of these
Last Answer : (C) Minimum effect of careless holding on the result
Description : Pile foundations are generally preferred to for (A) Bridge foundations (B) Sky scrapper buildings (C) Residential buildings (D) Runways
Last Answer : Answer: Option B
Description : For the movement of vehicles at an intersection of two roads, without any interference, the type of grade separator generally preferred to, is (A) Delta (B) Trumpet (C) Diamond interchange (D) Clover leaf
Last Answer : Answer: Option D
Description : When the width of car parking space and width of street are limited, generally preferred parking system is (A) Parallel parking (B) 45° angle parking (C) 65° angle parking (D) 90° angle parking
Last Answer : Answer: Option A