Description : Copper substances when exposed to air gains a green coating due to the formation of: (1) CuO (2) CuCO3 Cu(OH)2 (3) CuSO4 (4) Cu(NO3)2
Last Answer : (2) CuCO3 Cu(OH)2 Explanation: When copper is exposed to air, it reacts with moist carbon dioxide in the air and slowly loses its shiny brown surface and gains a green coat. This green substance is ... Cu(OH)2). The formation of this green coating on the surface of a copper object corrodes it.
Description : CuO + H2 = Cu + H2O. This equation is an example of - (1) Oxidation (2) Decomposition (3) Reduction (4) Redox
Last Answer : (4) Redox
Description : Acetaldehyde on treatment with Fehling's solution gives a precipitate of (a) Cu (b) Cu2O (c) CuO (d) None of these
Last Answer : Cu2O
Description : Identify the substances that are oxidised and the substances which are reduced in the following reactions. (i) 4Na(s) + O2(g) → 2Na2O(s) (ii) CuO (s) + H2(g) → Cu (s) + H2O(l) -Chemistry-10
Last Answer : (i) Substances oxidised is Na as it gains oxygen and oxygen is reduced. (ii) Substances reduced is Cu as hydrogen is oxidised as it gains oxygen.
Description : A green coloured solid compound ̳X , gets oxidized to reddish brown solid in presence of air. ̳X on heating gives brown coloured solid ̳Y and two pungent smelling gases ̳A and ̳B . ̳A turns acidified potassium ... , SO 3 , decomposition (d) FeSO 4 , Fe 2 O 3 , SO 3 , SO 2 , decomposition
Last Answer : (c) FeSO 4 , Fe 2 O 3, SO 2 , SO 3 , decomposition
Description : When copper pyrites is roasted in excess of air, a mixture of `CuO + FeO` is formed. `FeO` is present as impurity. This can be removed as slag during
Last Answer : When copper pyrites is roasted in excess of air, a mixture of `CuO + FeO` is formed. `FeO` is present ... a basic flux D. CaO, which is a basic flux
Description : (a) What are fuel cells? Explain the electrode reactions involved in the working of H2 – O2 fuel cell. (b) Represent the galvanic cell in which the reaction Zn (s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s) takes place. -Chemistry
Last Answer : (a) Fuel cells : These cells are the devices which convert the energy produced during combustion of fuels like H2, CH4, etc. directly into electrical energy. The electrode reaction for H2 – O2 fuel cell : (b) The galvanic cell may be represented as Zn (s) | Zn2+ (1M) || Cu2+ (1M) | Cu (s)
Description : Identify the type of reaction(s) in the following equations. (i)CH4 + 2O2 CO2 + 2 H2O (ii) Pb(NO3)2 + 2KI ——–>Pbl2 + 2KNOs (iii) CaO + H2O ——–> Ca(OH)2 (iv) CuSO4 + Zn ——–> ZnSO4 + Cu -Chemistry
Last Answer : Answer. (i) Combustion reaction and oxidation reaction. (ii)Double displacement reaction and precipitation reaction. (iii) Combination reaction. (iv) Displacement reaction.
Description : Amongst `[TiE_(6)]^(2-), [CoF_(6)]^(3-), Cu_(2)Cl_(2)` and `[NiCl_(4)]^(2-)` [Atomic no. `Ti = 22, Co = 27, Cu = 29, Ni = 28`] the colourless species
Last Answer : Amongst `[TiE_(6)]^(2-), [CoF_(6)]^(3-), Cu_(2)Cl_(2)` and `[NiCl_(4)]^(2-)` [Atomic no. `Ti = 22, ... (2)Cl_(2)` D. `TiF_(6)^(2-) and Cu_(2)Cl_(2)`
Description : The deficiencies of micronutrients, not only affect growth of plants but also vital functions such as photosynthetic and mitochondrial electron flow. Among the list given below, which group of three elements shall affect most, both ... , Mo (b) Ca, K, Na (c) Mn, Co, Ca (d) Cu, Mn, Fe
Last Answer : d) Cu, Mn, Fe
Description : Assertion :- In the reaction `Zn(s)+cu^(+2)(aq)rarrZn^(+2)(aq)+Cu(s)` `Cu^(+2)` ions act as oxidising agent and Zn atoms act as a reducing agent. Reas
Last Answer : Assertion :- In the reaction `Zn(s)+cu^(+2)(aq)rarrZn^(+2)(aq)+Cu(s)` `Cu^(+2)` ions ... the Reason is False. D. If both Assertion & Reason are False.
Description : `underset("Calcium carbide")(CaC_(2))overset(H_(2)O)(to)(A)overset("Red hot Cu tube")(to)(B)`, Product (B) of the reaction is:
Last Answer : `underset("Calcium carbide")(CaC_(2))overset(H_(2)O)(to)(A)overset("Red hot Cu tube")(to)(B)`, Product (B) of the reaction is: A. B. C. D.
Description : Match each of the reaction given in Column I with the corresponding product(s) given in Column II. `{:("Column I","Column II"),(A. "Cu+dil. HNO"_(3),p
Last Answer : Match each of the reaction given in Column I with the corresponding product(s) given in Column II. `{:("Column I"," ... (,t. "Zn"("NO"_(3))_(2)):}`
Description : The nuclear reaction `""_(29)^(63)Cu +""_(2)^(4)He rarr ""_(17)^(37)Cl + ""_(1)^(1)H + 16""_(0)^(1)n` is referred to as
Last Answer : The nuclear reaction `""_(29)^(63)Cu +""_(2)^(4)He rarr ""_(17)^(37)Cl + ... reaction B. fusion reaction C. fission reaction D. chain reaction
Description : Which of the following reaction(s) take place in Bessemer converter for the extraction of Cu?
Last Answer : Which of the following reaction(s) take place in Bessemer converter for the extraction of Cu? A. `2CuFeS_(2) + ... ` D. `FeO + SiO_(2) rarr FeSiO_(3)`
Description : Calculate the number of Cu atoms in 0.635g of Cu. -Chemistry
Last Answer : No. of moles of Cu = Mass of Cu/Atomic mass = 0.635/63.5 =0.01 mole No. of Cu atoms = No. of moles × Avogadro constant = 0.01 × 6.022 × 1023 = 6.022 × 1023 Cu atoms.
Description : the number of Cu 's zeros in CuSO4 ?
Last Answer : CuSO4 - Cu 's zaron number +2
Description : The metal that is used as a catalyst in the hydrogenation of oils is - (1) Pb (2) Ni (3) Cu (4) Pt
Last Answer : (2) Ni Explanation: The catalyst used in hydrogenation of oils is nickel. It is used to speed up the reaction.
Description : The wire of flash bulbs is made up of – (1) Mg (2) Ba (3) Cu (4) Ag
Last Answer : (1) Mg Explanation: The wire of flash bulbs is made up of magnesium. Magnesium filaments are contained in bulbs filled with oxygen gas, and electrically ignited by a contact in the camera shutter.
Description : Brass is an alloy of : (1) Cu, Al and Zn (2) Cu and Sn (3) Cu and Zn (4) Al and Mg
Last Answer : (3) Cu and Zn Explanation: Brass is an alloy made of copper and zinc. The proportions of zinc and copper can be varied to cre-ate a range of brasses with varying properties. By comparison, bronze is principally an alloy of copper and tin.
Description : (a). Which is largest in size- Cu+ , Cu+2, Cu and why? (b). which element in the periodic table has the highest ionization enthalpy? (c). Which element is more metallic in the periodic table.?
Last Answer : Ans. (a). Cu is largest due to less effective nuclear charge. It has 29 electrons, 29 protons, Cu+ has 28 electrons and 29 protons, Cu2+ has 27 electrons and 29 protons. (b). He has highest ionization enthalpy. (c). Mg is more metallic due to lower ionization energy
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 : The wire of flash bulbs is made up of (1) Mg (2) Ba (3) Cu (4) Ag
Last Answer : Mg
Last Answer : Cu and Zn
Description : Photo chemical smog is a result-ant of the reaction among – (1) High concentration of NO2, O3, and CO in the evening (2) CO, CO2 and NO2 at low temperature (3) CO, O2 and peroxy acetyl nitrate in the presence of Sunlight (4) NO2, O3 and peroxy acetyl nitrate in the presence of Sunlight
Last Answer : (4) NO2, O3 and peroxy acetyl nitrate in the presence of Sunlight Explanation: Photochemical smog is a unique type of air pollution which is caused by reactions between sunlight and pollutants like hydrocarbons and nitrogen dioxide (NO and NO2).
Description : In which of the following reactions, standard reaction entropy change (S°) is positive and standard Gibb's energy change (G°) decreases sharply with increasing temperature? (1) 2 2 1 1 1 C graphite O (g) CO (g) 2 2 2 (2) 2 1 C ... CO(g) O (g) CO (g) 2 (4) 2 1 Mg(s) O (g) MgO(s) 2
Last Answer : C graphite O (g) CO(g)
Description : Are there any pre-NGE pre-CU Star Wars Galaxies players here?
Last Answer : I played SWG for three years..wow! pre CU…been a long since I heard that term.. I was on Sunrunner…you?
Description : (i) Substances oxidised is Na as it gains oxygen and oxygen is reduced. (ii) Substances reduced is Cu as hydrogen is oxidised as it gains oxygen. -Chemistry-10
Last Answer : During this reaction, the sodium is gaining oxygen and is being oxidized. Oxygen is getting reduced. During this reaction, copper oxide is losing oxygen and is being reduced. The hydrogen is gaining oxygen and is being oxidized.
Description : A spherical iron shell with external diameter 21 cm weighs 22775 x 5/21 grams. Find the thickness of the shell if the metal weighs 10 gms per cu cm. -Maths 9th
Last Answer : answer:
Description : It is responsible for all numerical and logical calculations. (a) CPU (b) CU (c) MU (d) ALU -Technology
Last Answer : (d) ALU is a digital circuit in which numerical and logical operations are defined.
Description : Which of the following does not represent an I/O device? (a) Speaker (b) Plotter (c) Joystick (d) CU -Technology
Last Answer : (d) CU is used to co-ordinate the input and the output devices of a computer system.
Description : PROBLEM EA Sample of moist soil has a water content of 20.0% and the moist unit weight of 21.09 KN/cu.meter. The specific gravity of the soil is 2.75. Compute the degree of saturation and the value of porosity?
Last Answer : two seconds
Description : What is the atomic number of Cu ?
Last Answer : The atomic number of Cu is 29
Description : Cu containing respiratory pigment is `:`
Last Answer : Cu containing respiratory pigment is `:` A. Haemoglobin B. Haemocyanin C. Chlorocruorin D. All the above
Description : Which of the following reactions is not involved in extraction of Cu from copper pyrite ?
Last Answer : Which of the following reactions is not involved in extraction of Cu from copper pyrite ? A. `Cu_(2)S * Fe_(2 ... 2)` D. `FeO+ SiO_(2) rarr FeSiO_(3)`
Description : A square-based tank of capacity 250 cu m has to bedug out. The cost of land is Rs 50 per sq m. The cost of digging increases with the depth and for th
Last Answer : A square-based tank of capacity 250 cu m has to bedug out. The cost of land is Rs 50 per ... the dimensions of the tank for the least total cost.
Description : Cu is present in
Last Answer : Cu is present in A. Plasmalemma B. Plastoquinone C. Plastocyanin D. Ferredoxin
Description : Assertion :- `Zn(s)+Cu^(+2)(aq)rarr Zn^(+2)(aq)+Cu(s)` can be spilt into following half reactions `{:(Zn(s)rarrZn^(+2)+2e^(-),),(,"(Oxidation half rea
Last Answer : Assertion :- `Zn(s)+Cu^(+2)(aq)rarr Zn^(+2)(aq)+Cu(s)` can be spilt into following half ... Reason is False. D. If both Assertion & Reason are False.
Description : `Ph-CH=CH-underset(O)underset(C)-H overset((i) CH_(3)CH_(2)MgBr)to overset((ii) H_(3)O^(o+))to(X) overset(Cu,Delta)to(Y)`
Last Answer : `Ph-CH=CH-underset(O)underset(C)-H overset((i) CH_(3)CH_(2)MgBr)to overset((ii) H_(3)O^(o+))to(X) ... -underset(O)underset(||)(C)-CH=CH-CH_(2)-CH_(3)`
Description : The following compounds are heated (i) `KNO_(3)` (ii) `Cu(NO_(3))_(2)` (iii) `Pb(NO_(3))_(2)` (iv) `NH_(4)NO_(3)` . Which of the following statement/s
Last Answer : The following compounds are heated (i) `KNO_(3)` (ii) `Cu(NO_(3))_(2)` (iii) `Pb(NO_(3)) ... and (iii) liberate `O_(2)` D. All statements are correct
Description : Cold dil. `H_(2)SO_(4)` will completely dissolve : (i) Pb (ii) `Fe_(3)O_(4)` (iii) Fe (iv) Cu (v) Mg (vi) MgO (vii) `CoCO_(3)` (viii) `CuCO_(2)` (ix)
Last Answer : Cold dil. `H_(2)SO_(4)` will completely dissolve : (i) Pb (ii) `Fe_(3)O_(4)` (iii) Fe (iv) Cu (v) ... ) `CoCO_(3)` (viii) `CuCO_(2)` (ix) `SrCO_(3)`
Description : The IUPAC name of complex `[Cu(en)_(2)(H_(2)O)_(2)]^(22+)`
Last Answer : The IUPAC name of complex `[Cu(en)_(2)(H_(2)O)_(2)]^(22+)` A. ethylene ... C. diaquobisdietyleamineCU(II)ion D. diaquobis(ethylenediamine)cuprate(II)
Description : Ammonia forms the complex `[Cu(NH_3)_4]^(2+)` with copper ions in alkaline solution but not in acid solution. The reasons for it is:
Last Answer : Ammonia forms the complex `[Cu(NH_3)_4]^(2+)` with copper ions in alkaline solution but not in ... ` ions and `NH_(3)` molecules are not available.
Description : A list of species having the formula of `XZ_(4)` is given below `XeF_(4), SF_(4), SiF_(4), BF_(4)^(-), BrF_(4)^(-), [Cu(NH_(3))4]^(2+),[FeCl_(4)]^(2-)
Last Answer : A list of species having the formula of `XZ_(4)` is given below `XeF_(4), SF_(4), SiF_ ... the total number of species having a square planar shape is
Description : The compound formed in the borax bead test of `Cu^(2+)` ion in oxidising flame is :
Last Answer : The compound formed in the borax bead test of `Cu^(2+)` ion in oxidising flame is : A. Cu B. `CuBO_(2)` C. `Cu(BO_(2))_(2)` D. None of these
Description : Assertion: Cu-T and Cu-7 do not suppress sperm motility. Reason: Hormones released by them affect sperm motility.
Last Answer : Assertion: Cu-T and Cu-7 do not suppress sperm motility. Reason: Hormones released by them affect ... D. If both the assertion and resson are false.