Description : Assertion : Reduction of ZnO with carbon is done at `1100^(@)C`. Reason : At this temperature, `DeltaG^(@)` is negative and the process is spontaneous
Last Answer : Assertion : Reduction of ZnO with carbon is done at `1100^(@)C`. Reason : At this temperature, ... ^(@)` is negative and the process is spontaneous.
Description : In which of the following reactions,standard reaction entropy change`(DeltaS^(@))`is positive and standard Gibb,s energy change`(DeltaG^(@))`decreases
Last Answer : In which of the following reactions,standard reaction entropy change`(DeltaS^(@))`is positive and standard Gibb,s ... (2)O_(2)(g)rarr CO_(2)(g)`
Description : Consider the following reactions at `1000^(@)C`. (A) `Zn_((s))+1/2 O_(2(g)) rarr ZnO_((s)), DeltaG^(@)=-360` kJ/mol (B) `C_("(gra)")+1/2 O_(2(g)) rarr
Last Answer : Consider the following reactions at `1000^(@)C`. (A) `Zn_((s))+1/2 O_(2(g)) rarr ZnO_((s)), DeltaG^( ... a) and (b) are true D. both (a) and (b) false
Description : `DeltaG^(@) vsT` plot in the Ellingham diagram slopes down for the reaction.
Last Answer : `DeltaG^(@) vsT` plot in the Ellingham diagram slopes down for the reaction. A. `Mg+(1)/(2)O_(2)toMgO` B. ` ... (2)toCO` D. `CO+(1)/(2)O_(2)toCO_(2)`
Description : Consider the following reaction at `1000^(@)C` `(A) Zn_((s))+(1)/(2)O_(2(s))+ZnO_(s),DeltaG^(0)=-360kJ"mole"^(-1)` (B) `(B) Cn_((s))+(1)/(2)O_(2(g))to
Last Answer : Consider the following reaction at `1000^(@)C` `(A) Zn_((s))+(1)/(2)O_(2(s))+ZnO_(s),DeltaG^ ... 1 and 2 are true D. Both statement 1 and 2 are false
Description : (A): At 1200K iron can be reduce cuprous oxide (R )L: At 1200K, `Fe+Cu_(2)O to FeO+2Cu` `DeltaG=-300kj//"mole"`
Last Answer : (A): At 1200K iron can be reduce cuprous oxide (R )L: At 1200K, `Fe+Cu_(2)O to FeO+2Cu` ` ... incorrect D. If (A) is incorrect but (R ) is correct
Description : Correct statements from the graph I) Above 1073 K,`DeltaG^(0)` for the formation of `F_(2)O_(3)` is less negative than `DeltaG^(0)` for the formation
Last Answer : Correct statements from the graph I) Above 1073 K,`DeltaG^(0)` for the formation of `F_(2)O_(3)` is less ... I B. I,II only C. I,II,III only D. All
Description : (A) The reduction reaction, `Cr_(2)O_(3)+2Al to Al_(2)O_(3)+2Cr, DeltaG^(0)=-421KJ` is not possible at room temperature (R ) Certain amount of activat
Last Answer : (A) The reduction reaction, `Cr_(2)O_(3)+2Al to Al_(2)O_(3)+2Cr, DeltaG^(0)=-421KJ` is not ... incorrect D. If (A) is incorrect but (R ) is correct
Description : For which one of the following reaction, the graph of `DeltaG` against T is almost horizontal to temperature axis
Last Answer : For which one of the following reaction, the graph of `DeltaG` against T is almost horizontal to temperature axis A. ... ((s))+O_(2(g)) to 2MgO(g)`
Description : Use of flux during soldering is done to (A) Increase fluidity of solder by lowering its melting temperature (B) Prevent oxide formation (C) Wash away surplus solder (D) Full up the joint gap
Last Answer : (B) Prevent oxide formation
Description : Assertion : In the human the temperature of scrotum is `2-2.5^(@)C` lesser then normal body temperature . Reason : Formation of sperm does not occur a
Last Answer : Assertion : In the human the temperature of scrotum is `2-2.5^(@)C` lesser then normal body ... False . D. If both Assertion & Reason are False.
Description : The formation of oxide film on a metal due to atmospheric exposure reduces its (A) Toughness (B) Stiffness (C) Creep limit (D) All (A), (B) & (C)
Last Answer : (C) Creep limit
Description : Which metal does not undergo corrosion due to the formation of oxide layer? (1) Copper (2) Iron (3) Aluminium (4) Zinc
Last Answer : Aluminium
Description : Assertion (A): There is no reaction known for which `DeltaG` is positive, yet it is spontaneous. Reason (R ) : For photochemical reaction, `DeltaG` is
Last Answer : Assertion (A): There is no reaction known for which `DeltaG` is positive, yet it is spontaneous. ... False. D. If both Assertion & Reason are false.
Description : At the point of intersection for any two reactions for any two reactions in Ellingham diagram, the gibbs energy `(DeltaG)` changes becomes
Last Answer : At the point of intersection for any two reactions for any two reactions in Ellingham diagram, the gibbs energy `(DeltaG ... `gt1` B. 1 C. `lt0` D. 0
Description : Stainless steel is welded with difficulty because of (A) Its high melting temperature (B) Chances of cracking (C) Oxide film formation (D) Chromium carbide formation
Last Answer : Option C
Description : Some statement about Ellingham diagram (a) Increase in the slope of the line on +ve side indicates the phase ransformation (b) Metal oxide decomposes
Last Answer : Some statement about Ellingham diagram (a) Increase in the slope of the line on +ve side indicates the phase ... C. Only b and c D. a,b and c
Description : Statement-1: The reduction of a metal oxide is easier if the metal formed is in liquid state at the temperature of reduction. Statement-2: The value o
Last Answer : Statement-1: The reduction of a metal oxide is easier if the metal formed is in liquid state at ... . Statement-1 is false but Statement -2 is true
Description : which of the following sulphides cannot be reduced to metal by `H_(2)`at about `1000^(@)`C?
Last Answer : which of the following sulphides cannot be reduced to metal by `H_(2)`at about `1000^(@)`C? A. HgS B. PbS C. `CS_(2)` D. `Bi_(@)S_(3)`
Description : Pick out the wrong statement. (A) Addition of methane to the furnace atmosphere reduces decarburising by hydrogen (B) Nitrogen in presence of steam decor-burises high carbon steel, whereas hydrocarbon ... the metal surface) cause nitride formation with increase in surface hardness (D) None of these
Last Answer : (D) None of these
Description : With increase in temperature, the electrical conductivity of a __________ decreases. (A) Semi-conductor (B) Metal or alloy (C) Dielectric (D) None of these
Last Answer : (A) Semi-conductor
Description : The formation of the oxide `M_(x)O_(y)`per mole of `O_(2)` cinsumed is written a `(2x)/(y)M_((S))+O_(2(g))to(2)/(y)M_(x)O_(y)` the free energy change
Last Answer : The formation of the oxide `M_(x)O_(y)`per mole of `O_(2)` cinsumed is written ... from the following two reactions. Choose the correct statement
Description : Oxide of sulphur present in the atmosphere are washed down by rains to cause – (1) Depletion of fossil fuel reserves (2) Eutrophication in lakes (3) Lowering of pH of soil (4) Industrial smog formation
Last Answer : (1) Depletion of fossil fuel reserves Explanation: The oxide of Sulphur (Sulphur Dioxide) is washed down on earth as acid rain.
Description : Which of the following are responsible for the formation of photochemical smog ? 1. Light intensity 2. Ratio of hydrocarbons to nitric oxide 3. CO2 4. Hydrocarbon reactivity 5. SO2 (a) 1, 2, 3, 4 and 5 (b) 1, 2 and 4 only (c) 2, 3 and 4 only (d) 2, 3 and 5 only
Last Answer : (b) 1, 2 and 4 only
Description : Which one of the following impurity is not desirable in the soil used for brick formation a) Alkali b) Kankar c) Iron oxide d) Alkali & Kankar*
Last Answer : d) Alkali & Kankar*
Description : Oxide of sulphur present in the atmosphere are washed down by rains to cause : (1) Depletion of fossil fuel reserves (2) Eutrophication in lakes (3) Lowering of pH of soil (4) Industrial smog formation
Last Answer : Depletion of fossil fuel reserves
Description : __________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C. (A) Veneering (B) Galvanising (C) Electroplating (D) Calorising
Last Answer : (D) Calorising
Description : ABCD is a quadrilateral in which `/_A= 60^(@), /_ B= 70^(@), /_ C =110^(@)` and `/_ D =120^(@)`. The number of pairs of parallel lines is `"__________
Last Answer : ABCD is a quadrilateral in which `/_A= 60^(@), /_ B= 70^(@), /_ C =110^(@)` and ... )`. The number of pairs of parallel lines is `"________________"`.
Description : For a temperature difference `DeltaT=20.0^(@)C`, one slab of material conducts `10.0W//m^(2)` , another of the same shape conduct `20.0W//m^(2)`. What
Last Answer : For a temperature difference `DeltaT=20.0^(@)C`, one slab of material conducts `10.0W//m^(2)` , another of the ... C. `20/3 W//m^(2)` D. none of these
Description : A piston filled with `0.04` mole of an ideal gas expands reversible from `50.0mL` at a constant temperature of `37.0^(@)C` . As it does so, it absorbs
Last Answer : A piston filled with `0.04` mole of an ideal gas expands reversible from `50.0mL` at a constant temperature of `37. ... J` D. `q= +208 J, w=+208 J`
Description : If `0.5 `mole `H_(2)` is reacted with 0.5 mole `I_(2)` in a ten `-` litre container at `444^(@)C` and at same temperature value of equilibrium constan
Last Answer : If `0.5 `mole `H_(2)` is reacted with 0.5 mole `I_(2)` in a ten `-` litre container at `444^(@)C` and at ... B. `(1)/(7)` C. `sqrt((1)/(7))` D. 49
Description : At 0^(@)C soil temperature the rate of water absorption
Last Answer : At 0^(@)C soil temperature the rate of water absorption A. Increases B. Not effected C. Derreases D. Appreciable
Description : What will happen to spermatozoa at `0^(@)C` temperature :-
Last Answer : What will happen to spermatozoa at `0^(@)C` temperature :- A. All sperm will die B. ... They will become inactive temporarily D. Tails will be lost
Description : When `PtE_(6)` vapour mixed with an equal volume of Xe, the gases combined immediatedly at room temperature and produces a yellow solid X at `66^(@)C`
Last Answer : When `PtE_(6)` vapour mixed with an equal volume of Xe, the gases combined immediatedly at room temperature and produces ... ]^(+) [Pt_(2)F_(11)]^(-)`
Description : The resistance of a silver wire at `0^(@)C " is " 1.25 Omega`. Upto what temperature it must be heated so that its resistance is doubled ? The tempera
Last Answer : The resistance of a silver wire at `0^(@)C " is " 1.25 Omega`. Upto what temperature ... temperature be same for all silver conductors of all shapes ?
Description : The temperature coefficent of resistance of a wire is 0.00125 per `.^(@)C`, At 300 K, its resistance is `1Omega`. At what temperature will its resista
Last Answer : The temperature coefficent of resistance of a wire is 0.00125 per `.^(@)C`, At 300 K, ... At what temperature will its resistance become `2 Omega` ?
Description : The temperature coefficient of copper is `0.004^(@)C^(-1)`. Find the resistance of a 5 m long copper wire of diameter 0.2 mm at `100^(@)C`, if the res
Last Answer : The temperature coefficient of copper is `0.004^(@)C^(-1)`. Find the resistance of a 5 m long copper wire of ... `0^(@)C` is `1.7xx10^(-8) Omega` m.
Description : The temperature coefficient of a resistance wire is `0.00 12.5^(@)C^(-1)`. At 300 K, its resistance is `1 Omega`. At what temperature the resistance o
Last Answer : The temperature coefficient of a resistance wire is `0.00 12.5^(@)C^(-1)`. At 300 K, its ... the resistance of the wire will be `2 Omega` ?
Description : The temperature coefficient of resistance of the material of a wire is `0.00125^(@)C^(-1)`. Its resistance at `27^(@)C` is `1 Omega`. At what temperat
Last Answer : The temperature coefficient of resistance of the material of a wire is `0.00125^(@)C^(-1)`. Its resistance at ... K B. 1100 K C. 1400 K D. 1127 K
Description : An electric immersion heater of `1.08 kW` is immersed in water . After it has reaches a temperature of `100^(@)C` , how much time will be required to
Last Answer : An electric immersion heater of `1.08 kW` is immersed in water . After it has reaches a temperature of `100^(@)C` ... 50 s B. 420 s C. 105 s D. 105 s
Description : The resistance of a wire at `20^(@)C` is `20Omega` and at `500^(@)C` is `60Omega`. At which temperature its resistance will be `25Omega`?
Last Answer : The resistance of a wire at `20^(@)C` is `20Omega` and at `500^(@)C` is `60Omega`. At which temperature its ... @)C` C. `70^(@)C` D. `80^(@)C`
Description : You are provided with magnesium ribbon and sulpher powder. Explain with the help of an activity that metal oxides are basic and non-metal oxide are acidic in nature. -Chemistry
Last Answer : Aim: To test the nature of oxides formed by metals and non-metals. Materials Required: Sulphur powder, Mg ribbon, water, blue litmus paper, red litmus paper. Procedure: 1.Take magnesium ribbon ... the metallic oxides are basic in nature whereas most of the non-metallic oxides are acidic in nature.
Description : Why Transient Metal Oxide Is Used To Make Stained Glass ?
Last Answer : Degeneration of electrons occurs in the d orbitals of their last orbits when transition metals form compounds . So their compounds (silicates) are colored. This is why transition metal oxides are used to make stained glass.
Description : Metal carbonates decompose on heating to give metal oxide and carbon dioxide. Which of the metal carbonates is most stable thermally?
Last Answer : Metal carbonates decompose on heating to give metal oxide and carbon dioxide. Which of the metal carbonates is most ... C. `SrCO_(3)` D. `BaCO_(3)`
Description : A metal oxide has `40%` oxygen. The equivalent weight of the metal is:
Last Answer : A metal oxide has `40%` oxygen. The equivalent weight of the metal is:
Description : If the equivalent mass of a metal is double that of oxygen then the weight of its oxide is ___ times greater than the weight of the metal.
Last Answer : If the equivalent mass of a metal is double that of oxygen then the weight of its oxide is ___ times greater than the ... A. 1.5 B. 2 C. 0.5 D. 3
Description : `3 g` of an oxide of a metal is converted completely to `5 g` chloride. Equivalent weight of metal is:
Last Answer : `3 g` of an oxide of a metal is converted completely to `5 g` chloride. Equivalent weight of metal is: A. 33.25 B. 3.325 C. 12 D. 20
Description : X gm of metal gave Y gm of its oxide, so equivalent mass of metal is :
Last Answer : X gm of metal gave Y gm of its oxide, so equivalent mass of metal is : A. `(y-x)/(x)xx8` B. `(x)/((y-x))xx8` C. `(x)/(y)xx8` D. `(x+y)/(x)xx8`
Description : (A) Auto reduction of ore is used for the extraction of copper (R ) The sulphide ore of copper reacts with its oxide to the give the metal
Last Answer : (A) Auto reduction of ore is used for the extraction of copper (R ) The sulphide ore of copper reacts ... . If (A) is incorrect but (R ) is correct
Description : The oxide of a metal (R ) can be reduced by the metal (P) and metal (R ) can reduce the oxide of metal (Q). Then the decreasing order of the reactivit
Last Answer : The oxide of a metal (R ) can be reduced by the metal (P) and metal (R ) can reduce the oxide of metal (Q). Then ... C. `R gt P gt Q` D. `Q gt P gt R`