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 : Cuo + c = what is the reaction in cu + co ?
Last Answer : The reaction is an oxidation reaction. This reaction is also called carbon deoxidation reaction.
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 : 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 : 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 : The oxidation-reduction system having the highest redox potential is (A) Ubiquinone ox/red (B) Fe3+ cytochrome a/Fe2+ (C) Fe3+ cytochrome b/Fe2+ (D) NAD+/NADH
Last Answer : Answer : B
Description : When steam is passed over coal resulting in the endothermic reaction represent by, C + H2O = CO + H2 , it is called the __________ of coal. (A) Carbonisation (B) Oxidation (C) Coalification (D) Gasification
Last Answer : (D) Gasification
Description : The working of a dry cell is based on - (1) Decomposition reaction (2) Spontaneous oxidation-reduction reaction (3) Combination reaction. (4) Electrolysis
Last Answer : (4) Electrolysis Explanation: A dry cell is a type of battery that uses a paste electrolyte, with only enough moisture to allow current to flow. It works in accordance with Faraday's law of ... of the cell (the positive electrode), and the space between them is filled with an electrolyte paste.
Description : Bleaching action of chlorine is by - (1) Decomposition (2) hydrolysis (3) reduction (4) oxidation
Last Answer : (4) oxidation Explanation: Chlorine bleaches by the process of oxidation. It needs moisture for its bleaching action. Chlorine reacts with water to form hydrochloric and hypochlorous acids.
Description : Sulphur dioxide bleaches colouring matter by – (1) Reduction (2) Dehydration (3) Decomposition (4) Oxidation
Last Answer : (1) Reduction Explanation: Sulphur dioxide gas exhibits bleaching properties in presence of moisture. It dissolves in water liberating nascent hydrogen. Nascent hydrogen removes oxygen atoms from the colouring matter (reduces colouring matter) and it loses its colour.
Description : Bleaching action of chlorine is by - (1) decomposition (2) hydrolysis (3) reduction (4) oxidation
Description : Which of the following is a physical change? (1) oxidation (2) reduction (3) sublimation (4) decomposition
Last Answer : (3) sublimation Explanation: Sublimation is a type of phase transition, or a change in a state of matter, just like melting, freezing, and evaporation.
Description : Which of the following reactions involve NEITHER oxidation nor reduction? w) burning antimony in chlorine x) decomposition of potassium chlorate y) reaction of sodium with water z) reaction of potassium hydroxide with nitric acid
Last Answer : ANSWER: Z -- REACTION OF POTASSIUM HYDROXIDE WITH NITRIC ACID
Description : The working of a dry cell is based on (1) Decomposition reaction (2) Spontaneous oxidation-reduction reaction (3) Combination reaction (4) Electrolysis
Last Answer : Electrolysis
Description : Sulphur dioxide bleaches colouring matter by : (1) Reduction (2) Dehydration (3) Decomposition (4) Oxidation
Last Answer : Reduction
Description : What Sodium (Na) and water (H2O) undergo a chemical reaction that produces sodium hydroxide (NaOH and hydrogen gas (H2). Which equation represents this chemical reaction?
Last Answer : 2Na+2H20->2Na0H+H2 ::::apex
Description : Zn + 2 HCl = H2 + ZnCl, is an example of which type of reaction? (1) Double displacement reaction (2) Combination reaction (3) Single displacement reaction (4) Decomposition reaction
Last Answer : (3) Single displacement reaction Explanation: This reaction is an example of single displacement reaction. In Substitution or Single Replacement Reactions, a single free element replaces or is substituted for one of the elements in a compound.
Description : Decomposition of the acetyl salicylic acid at room temperature most likely would occur by (a) Oxidation of the ester (b) Reduction of the carboxylic acid (c) Hydrolysis of the ester
Last Answer : Ans: C
Description : Rusting is the process of – (1) Oxidation (2) Reduction (3) Decomposition (4) Displacement
Last Answer : (1) Oxidation Explanation: Rust is the process of iron (molecules) oxidizing into iron oxide, or rust. General formula of rust is Fe2O3.nH2O
Description : Bleaching action of chlorine is by----? A. Oxidation (Answer) B. Reduction C. Decomposition D. Hydrolysis
Last Answer : A. Oxidation (Answer)
Description : Rusting of Iron involves--------? A. Reduction B. Oxidation (Answer) C. Decomposition D. Displacement
Last Answer : B. Oxidation (Answer)
Description : During decomposition, energy is absorbed in the form of heat, light or electricity for breaking down the reactants which is known as: (a) exothermic reaction (b) endothermic reaction (c) reduction reaction (d) oxidation
Last Answer : (b) endothermic reaction
Description : Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas (N2) to the atmosphere? (a) Aerobic nitrate oxidation and nitrite reduction (b) ... fixation by Rhizobium in root nodules of legumes (d) Anaerobic ammonium oxidation and denitrification
Last Answer : (d) Anaerobic ammonium oxidation and denitrification
Description : Cement setting under water employs a/an __________ process. (A) Hydration (B) Decomposition (C) Oxidation (D) Reduction
Last Answer : (A) Hydration
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 : (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 : Water gas is the combination of – (1) CO and H2 (2) CO2 and H2 (3) CO and H2O (4) CO2 and CO
Last Answer : (1) CO and H2 Explanation: Water has is a synthesis gas, containing carbon monoxide (CO) and hydrogen has (H2). It is made by passing steam over a redhot carbon fuel such as coke. The reaction between steam and hydrocarbons produce the has mixture.
Description : Two half-reactions of an electrochemical cell are given below : MnO-4 (aq) + 8H+ (aq) + 5e- → Mn2+ (aq) + 4H2O (I), E° = 1.51 V Sn2+ (aq) → Sn4+ (aq) + 2e- ... the redox equation from the standard potential of the cell and predict if the reaction is reactant favoured or product favoured. -Chemistry
Last Answer : The reactions can be represented at anode and at cathode in the following ways : At anode (oxidation) : Sn2+ → = Sn4+ (aq) + 2e- ] 5 E° = + 0.15 V At cathode (reduction) : MnO-4(aq) + 8H+ ... = E°cathode - E°anode = 1.51 - 0.15 = + 1.36 V ∴ Positive value of E°cell favours formation of product.
Description : Two half-reactions of an electrochemical cell are given below : MnO-4 (aq) + 8H+ (aq) + 5e- → Mn2+ (aq) + 4H2O (I), E° = 1.51 V Sn2+ (aq) → Sn4+ (aq) + ... -reactions and calculate the cell potential from the standard potentials and predict if the reaction is reactant or product favoured. -Chemistry
Last Answer : The reactions can be represented at anode and at cathode in the following ways : At anode (oxidation) : Sn2+ → Sn4+ (aq) + 2e- ] 5 E° = + 0.15 V Af cathode (reduction) : MnO-4(aq) + 8H+ ( ... = E°cathode - E°anode = 1.51 - 0.15 = + 1.36 V ∴ Positive value of E°cell favours formation of product.
Description : If the more negative standard reduction potential of a redox pair, the greater the tendency to (A) To lose electrons (B) To gain electrons (C) To lose/gain electrons (D) To lose and gain electrons
Last Answer : A
Description : When volume of the equilibrium reaction C(s) + H2O(g) ⇌ CO(g) + H2(g) is increased at constant temperature the equilibrium will :
Last Answer : When volume of the equilibrium reaction C(s) + H2O(g) ⇌ CO(g) + H2(g) is increased at constant ... left c. be unaltered d. can not be predicted
Description : If you wanted to make 8.12 mole h2o how many moles of h2 would you need?
Last Answer : Feel Free to Answer
Description : Gobar gas contains mainly (a) CO2 + H2 (b) CO2 + H2O (c) CH4 only (d) CH4 + CO2.
Last Answer : (d) CH4 + CO2.
Description : Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O)? (A) Blast furnace coke (B) Low temperature coke (C) Anthracite coal (D) Sub-bituminous coa
Last Answer : (B) Low temperature coke
Description : Sometimes water is sprayed during coal charging in the coke oven, which helps in (A) Prevention of clinker formation in the oven (B) Controlling the dust nuisance while charging the coal (C) Reducing the cracking of hydrocarbons in ... represented by C + H2O = CO + H2 ) (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Which of the following reactions occuring during coal gasification is called the Neumann reversal reaction? (A) 2CO ↔ C + CO2 (B) CO + H2O ↔ CO2 + H2 (C) C + H2O ↔ CO + H2 (D) C + 2H2O ↔ CO2 + 2H2
Last Answer : (A) 2CO ↔ C + CO2
Description : The gasification reaction represented by, C + H2O = CO + H2 , is (A) Exothermic (B) Endothermic (C) Catalytic (D) Autocatalytic
Last Answer : (B) Endothermic
Description : The shift conversion reaction taking place during water gas manufacture is given by (A) C + H2O ↔ CO + H2 (B) C + 2H2O ↔ CO2 + 2H2 (C) CO + H2O ↔ CO2 + H2 (D) None of these
Last Answer : (C) CO + H2O ↔ CO2 + H2
Description : Given, 3H2 + CO = CH4 + H2O, KP = 10 1.84 and, 4H2 + CO2 = CH4 + 2H2O, KP = 10 1.17 the KP for the reaction CO + H2O = CO2 + H2 is (A) 10 3.01 (B) 10 -0.67 (C) 10 -3.01 (D) 10 0.67
Last Answer : (D) 10 0.67
Description : Pick out the exothermic reaction out of the following: (A) C + H2O = CO + H2 (B) CaC2 + H2O = Ca(OH)2 + C2H2 (C) MgCO3 = MgO + CO2 (D) All (A), (B) and (C)
Last Answer : (B) CaC2 + H2O = Ca(OH)2 + C2H2
Description : Which of the following is an endothermic reaction? (A) Absorption of SO3 in 98% H2SO4 (B) C + H2O = CO + H2 (C) Thermal dissociation of iron pyrites (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : The gasification reaction represented by, C + H2O = CO + H2 , is a/an __________ reaction. (A) Exothermic (B) Endothermic (C) Catalytic (D) Autocatalytic
Description : Forward reaction will be favoured for the exothermic reaction, represented by CO + H2O ⇌ CO2 + H2, by (A) Low temperature and high pressure (B) Low temperature and low pressure (C) High temperature and high pressure (D) High temperature and low pressure
Last Answer : (A) Low temperature and high pressure
Description : Assertion :- In a redox reaction, the oxidation number of the oxidant decreases while that of reductant increases. Reason :- Oxidant gains electron(s)
Last Answer : Assertion :- In a redox reaction, the oxidation number of the oxidant decreases while that of reductant ... D. If both Assertion & Reason are False.
Description : How many moles of H2 and N2 can be formed by the decomposition of 0.145 moles of ammonia, NH3?
Last Answer : All together now… WE WILL NOT DO YOUR HOMEWORK
Description : Main component of sewage gas produced during anaerobic decomposition of organic waste (by suitable bacteria) during sewage disposal is (A) H2 (B) CH4 (C) CO2 (D) N2
Last Answer : (B) CH4
Description : In case of the decomposition of hydroiodic acid (2HI ⇌ H2 + I2), addition of H2(at equilibrium condition) will (A) Increase the partial pressure of I2 (B) Decrease the partial pressure of HI (C) Diminish the degree of dissociation of HI (D) None of these
Last Answer : (C) Diminish the degree of dissociation of HI
Description : Oxygen has (+) oxidation number only in – (1) OF2 (2) Cl2O (3) H2O (4) N2O
Last Answer : (1) OF2 Explanation: In case of F2O, oxygen is not the most electronegative element. The fluorine is more electronegative and has an oxidation state of -1. In this case, the oxygen has an oxidation state of +2.
Description : Oxygen has (+) oxidation number only in (1) OF2 (2) Cl2O (3) H2O (2) N2O
Last Answer : OF2
Description : The thermal decomposition of alkanes in the absence of air is called : (a) Combustion (b) Oxidation (c) Cracking (d) Hydrogenation
Last Answer : Cracking