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 yellow coloured crystalline substance gave a colourless gas `X` on reaction with fluorine, which is thermally stable and has octahedral geometry. `X
Last Answer : A yellow coloured crystalline substance gave a colourless gas `X` on reaction with fluorine, which is ... and has octahedral geometry. `X` can be
Last Answer : A yellow coloured crystalline substance gave a colourless gas `X` on reaction with fluorine, which is thermally stable ... `SF_(2)` D. `S_(2)F_(6)`
Description : A yellow metallic powder is burnt in a stream of fluorine to obtain a colourless gas X which is thermally stable and chemically inert. Its molecule ha
Last Answer : A yellow metallic powder is burnt in a stream of fluorine to obtain a colourless gas X which is thermally stable ... and NaC1` D. `SF_(4) and SF_(6)`
Description : Assign the reason for the following: (a) Enthalpy of fusion of water is higher as compared to the hydrides of Sulphur & Selenium. (b) Water is quite stable and does not dissociate in to its elements even at high temperature.
Last Answer : Ans-a) Due hydrogen bond it has high latent heat of fusion b) Water is a stable compound and its decomposition is not thermodynamically feasible
Description : The chalcogen having same number of electrons both in penultimate and antipenultimate shells is
Last Answer : The chalcogen having same number of electrons both in penultimate and antipenultimate shells is A. O B. S C. Se D. Te
Description : Which of the following is a true Chalcogen
Last Answer : Which of the following is a true Chalcogen A. Nitrogen B. Oxygen C. Polonium D. Chlorine
Description : Is helium acidic reactive basic or stable?
Last Answer : Helium is an unreactive chemical element.
Description : Riboflavin is heat stable in (A) Acidic medium (B) Alkaline medium (C) Neutral medium (D) Both (A) and (C)
Last Answer : Answer : D
Description : Thiamin is heat stable in (A) Acidic medium (B) Alkaline medium (C) Both (A) and (B) (D) None of these
Last Answer : Answer : A
Description : How much more thermally conductive are copper pots and pans compared to aluminum or stainless steel?
Last Answer : Copper is amongst the most thermally conductive material on the market. In most cases, copper is too hot for most cooking purposes, which is why aluminum and stainless steel are more popular.
Description : Choose the wrong statement (a) Temperature of medium being cooled must be below that of the evaporator (b) Refrigerant leaves the condenser as liquid (c) All solar thermally operated absorption systems are capable only of intermittent operation (d) frost on evaporator reduces heat transfer
Last Answer : Ans: a
Description : Steam distillation is not recommended to be used, if the (A) Azeotropic mixture is to be separated and the final product is miscible with water (B) Liquids decompose, if ... unstable or has the tendency to react with other components associated with it, at the boiling temperature
Last Answer : (A) Azeotropic mixture is to be separated and the final product is miscible with water
Description : Out of 100 kcal/second of incident radiant energy on the surface of a thermally transparent body, 300 kcal/second is reflected back. If the transmissivity of the body is 0.25, the emissivity of the surface will be (A) 0.35 (B) 0.45 (C) 0.55 (D) 0.85
Last Answer : (B) 0.45
Description : The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is (A) 1.66 (B) 88.66 (C) 3.66 (D) Dependent on NRe only
Last Answer : (C) 3.66
Description : The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is (A) 2.36 (B) 4.36 (C) 120.36 (D) Dependent on NRe only
Last Answer : (B) 4.36
Description : Which is the most thermally efficient furnace? (A) Reheating furnace (B) Reverberatory furnace (C) Rotary kilns (D) Boiler furnace
Last Answer : (D) Boiler furnace
Description : Dark current in light detectors is caused by ∙ a. Thermally generated carriers in the diode ∙ b. The absence of light input ∙ c. Small leakage current ∙ d. Its imperfection
Last Answer : a. Thermally generated carriers in the diode
Description : Barrier potential in a P-N junction is caused by (A) Thermally generated electrons and holes. (B) Diffusion of majority carriers across the junction. (C) Migration of minority carriers across the junction. (D) Flow of drift current.
Last Answer : (B) Diffusion of majority carriers across the junction.
Description : It is a very hot day. You are in a special kitchen, in that there are no exits and the walls of this kitchen are thermally very well insulated. If you open the refrigerator door, the room will eventually: w) cool off. x) remain the same. y) heat up.
Last Answer : ANSWER: Y -- HEAT UP.
Description : Assertion :- Oxidation state of Hydrogen is `+1` in `H_(2)O` while `-1` in `CaH_(2)`. Reason :- `CaH_(2)` is a metal hydride and for metal hydrides, h
Last Answer : Assertion :- Oxidation state of Hydrogen is `+1` in `H_(2)O` while `-1` in `CaH_(2)`. ... Reason is False. D. If both Assertion & Reason are False.
Description : The correct statements(s) regarding hydrides `(H_(2)E)` of group -16 is/are
Last Answer : The correct statements(s) regarding hydrides `(H_(2)E)` of group -16 is/are A. The ... D. The reducing character of hydrides increases down the group
Description : The basic strength of the hydrides of group 15 elements :
Last Answer : The basic strength of the hydrides of group 15 elements : A. decreases on moving down the group ... first increases upto `AsH_(3)` and then decreases
Description : `DeltaH_"vaporisation"` (KJ/mol) are given for the hydrides of halogens in the following graph. The hydride HF will correspond to
Last Answer : `DeltaH_"vaporisation"` (KJ/mol) are given for the hydrides of halogens in the following graph. The hydride HF will ... . (B)Q C. (C)R D. (D)S
Description : Which of the following halogen hydrides will have the weakest conjugate base?
Last Answer : Which of the following halogen hydrides will have the weakest conjugate base? A. (A)HF B. (B)HCI C. (C)HBr D. (D)HI
Description : Asseration: The thermal stability of hydrides of oxygen family decrease with molecular weight. Reason: The decomposition of `M-H` bond requires lesser
Last Answer : Asseration: The thermal stability of hydrides of oxygen family decrease with molecular weight. Reason: The decomposition ... in `O-H` than `S-H`.
Description : (A) : Thermal stability of the hydrides of VIA group elements decreases from `H_(2)O` to `H_(2)Po` (R) : The heats of dissociation of M - H bond of hy
Last Answer : (A) : Thermal stability of the hydrides of VIA group elements decreases from `H_(2)O` to `H_(2)Po` (R) : ... is false D. (A) is false but (R) is true
Description : The statements regarding hydrides of VIA group elements are i) The order of volatility `H_(2)OltH_(2)TeltH_(2)SeltH_(2)S` ii) The order of B.P `H_(2)O
Last Answer : The statements regarding hydrides of VIA group elements are i) The order of volatility `H_(2)OltH_(2)TeltH_ ... are correct D. `i` & iii are correct
Description : The maximum bond angle in hydrides of group 16 elements is in
Last Answer : The maximum bond angle in hydrides of group 16 elements is in A. `H_(2)O` B. `H_(2)Se` C. `H_(2)S` D. `H_(2)Te`
Description : What is covalent hydrides?
Last Answer : Covalent hydrides are all the other compounds of hydrogen wher hydrogen is covalently bonded- typiccally sharing an electron pair as in CH4 (methane) which could be called carbon tetrahydride ... valence electronsand hydrogen forms negative ion gaining that electron in order to complete its shell.
Description : What are hydrides of boron called ?
Last Answer : Boranes
Description : What accounts for the formation of Boron Hydrides?
Last Answer : Ans. Because of small size of both B & H forms stable compound called Boron Hydrides.
Description : Give two examples of Interstitial Hydrides.
Last Answer : Ans-Transition metal hydrides are called Interstitial Hydrides T1 H1.8& T1H2 (non –stoichiometric hydrides)
Description : what do you understand by “Non stoichiometric hydrides”? Do you think this type of hydrides to be formed by alkali metals? Justify your answer.
Last Answer : Ans: Hydrides which are deficient in hydrogen and in which the ratio of hydrogen to metal is fractional are called non-stoichiometric hydrides. This type of hydrides are formed by d-and ... they form only stoichiometric hydrides. In other words alkali metals do not form non-stoichiometric hydrides.
Last Answer : Ans-Transition metal hydrides are called Interstitial Hydrides T1 H1.8& T1H2(non –stoichiometric hydrides)
Description : Name the classes of Hydrides to which H2O, B2H6 & NaH belong
Last Answer : Ans. H2O—Covalent B2H6- Covalent NaH- Ionic
Description : What do you understand by (1) electron-deficient,(ii) electron-précise and (iii) electron precise hydrides. Provide justification with suitable examples
Last Answer : Ans: Electron-deficient: the hydrides which contain less than eight electron in their outmost shell are called electron- deficient for exam B2H6 Electron- precise: These hydrides contain exact number of ... nomal covalent bond and are called as electron rich hydrides. For example NH3,PH3,H2O,H2S.
Description : Give one example of electron deficient Hydrides.
Last Answer : Ans.BH3
Description : `K_2S_2O_8` , acidic `K_2S_2O_8` and acidic `MnO_2` oxidise `I^(-), Br^(-) , Cl^(-)` to `I_2 , Br_2 and Cl_2` , respectively. From the given data the
Last Answer : `K_2S_2O_8` , acidic `K_2S_2O_8` and acidic `MnO_2` oxidise `I^(-), Br^(-) , Cl^(-)` to `I_2 , ... gt I_2 gt Br_2` D. `Cl_2 gt K_2 S_2O_8 gt Br_2`
Description : Two solutions A1 & A2 have pH value of 2 & 6 respectively. It implies that the solution (A) A1is more alkaline than solution A2 (B) A1is highly acidic (C) A2is very slightly acidic (D) Both (B) & (C)
Last Answer : (D) Both (B) & (C)
Description : For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively). (A) G is above B (B) B is above G (C) B & G coincide (D) None of these
Last Answer : (B) B is above G
Description : The Metacentric heights of two floating bodies A and B are 1 m and 1.5 m respectively. Select the correct statement. (A) The bodies A and B have equal stability (B) The body A is more stable than body B (C) The body B is more stable than body A (D) The bodies A and B are unstable
Last Answer : Answer: Option C