Description : . Photo-chemical reactions occur in presence of (A) Sunlight (B) Darkness (C) Solid catalysts (D) Monochromatic radiation only
Last Answer : (A) Sunlight
Description : What is the physical state of water at 12° C? (1) Gas (2) Solid (3) Liquid (4) Ionic
Last Answer : (3) Liquid Explanation: Water can occur in thretates solid (ice), liquid gas (vapor). It is liquid at 12 Celsius. This is the form water with which we are most familiar.
Description : Some substances are good conductor of electricity in both the solid and liquid states. These substances are generally-------? A. ionic substances B. metallic substances (Answer) C. molecular solids D. covalent network solids
Last Answer : B. metallic substances (Answer)
Description : (a) Show on a diagram the transfer of electrons between the atoms in the formation of MgO. Write symbols of cation and anion present in MgO. (b) Name the solvent in which ionic compounds are generally soluble. (c) Why are aqueous solutions of ionic compounds able to conduct electricity? -Chemistry
Last Answer : (b) Ionic compounds are soluble in water. (c) It is because aqueous solutions consist of ions which can move freely in them and carry current.
Description : Which of the following alkali metal ions has the lowest ionic mobility in aqueous solutions?
Last Answer : Which of the following alkali metal ions has the lowest ionic mobility in aqueous solutions? A. `Li^(+)` B. `Na^(+)` C. `Rb^(+)` D. `Cs^(+)`
Description : What Categories of materials suitable for use as containers of ionic solutions?
Last Answer : Glazed ceramics,plastic ,glass
Description : Ionic substances dissolve in water to form: w) highly acid solutions x) electrolytic solutions y) colloids z) emulsions
Last Answer : ANSWER: X -- ELECTROLYTIC SOLUTIONS
Description : Very dilute solutions are generally used in fermentation reactions for which the optimum temperature range is __________ °C. (A) -5 to 0 (B) 5 to 10 (C) 30 to 50 (D) 75 to 80
Last Answer : (C) 30 to 50
Description : In nature water may occur as (A) Liquid (B) Solid (C) Vapours (D) All the above
Last Answer : Answer: Option D
Description : Consider the following statements: 1. Propagation of a nerve impulse in a myelinated nerve fibre is different from that of unmyelinated fibre. 2. The impulse actually travels by leaping through the nodes of Ranvier in an unmyelinated fibre 3. ... incorrect? (a) 1, 2 (b) 1, 3, 4 (c) 2 only (d) 2, 3
Last Answer : Ans:(d)
Description : Under what conditions precipitation takes place in ionic reactions?
Last Answer : Ans. When ionic product is greater than solubility product.
Description : Raoult's law applies to the (A) All liquid solutions (B) Non-ideal solution only (C) Non-volatile solute (D) Solvents
Last Answer : (D) Solvents
Description : (a) Show the formation of Na2O by the transfer of electrons between the combining atoms. (b) Why are ionic compounds usually hard? (c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state? -Chemistry
Last Answer : (b) It is due to strong force of attraction between oppositely charged ions. (c) In solid state, ions are not free to move whereas in molten state ions are free to move, therefore, they conduct electricity in molten state.
Description : Why ionic crystals don't conduct electricity in the solid state?
Last Answer : In the solid state ionic crystals are not dissociated in ions.
Description : Ionic non polar solid dielectrics contain more than one type of atoms but no permanent dipoles. State True/False a) True b) False
Last Answer : a) True
Description : What is modern theory about the existence of the ionic compounds in solid state?
Last Answer : Ans: According to modern theory these exist in form of ions even in solid state for example, sodium chloride exist as Na+ Cl- . Whereas according to the ionic theory it exists as NaCl.
Description : Why ionic compounds are non conductor in solid state and conductor in molten or fused state?
Last Answer : Ans: This is because in solid state there are no free ions and their free movement isn’t possible but in molten or fused state the free movement of ions is possible, so these can conduct electric current.
Description : Those solutions in which there is no volume change upon mixing the components in the liquid state and which, when diluted do not undergo any heat change (i.e. heat of dilution is zero), are called __________ solutions. (A) Ideal (B) Real (C) Isotonic (D) None of these
Last Answer : (A) Ideal
Description : Solutions are the preferred medium for carrying out reactions because _______.?
Last Answer : both of these
Description : Hydrogen in liquid steels is dissolved (A) As tiny gas bubbles (B) In the atomic form (C) In the ionic form (D) In the molecular form
Last Answer : Option A
Description : Which of the following substances is an ionic netw solid? w) Diamond x) Table Salt y) Brass z) Dry ice
Last Answer : ANSWER: X -- TABLE SALT
Description : A net ionic equation does NOT show: w) electronic charges x) solid products (precipitates) y) spectator ions z) reacting species
Last Answer : ANSWER: Y -- SPECTATOR IONS
Description : Which one of the following statements concerning elements in the Periodic Table is correct? A Elements of the same group all have the same number of electrons in the outermost occupied electron shell. B ... (Group 17) are all gases at room temperature. E The Group 13 elements are all metals.
Last Answer : D) Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Description : Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are ... __________ °C. (A) 400-500 (B) 900-1000 (C) 1400-1500 (D) 1700-1800
Last Answer : (B) 900-1000
Description : In solid catalysed reactions the diffusional effects are more likely to affect the overall rate of reaction for (A) Fast reactions in catalyst of small pore diameter (B) Fast reaction in catalyst ... reactions in catalyst of small pore diameter (D) Slow reactions in catalyst of large pore diameter
Last Answer : (C) Slow reactions in catalyst of small pore diameter
Description : Non-catalytic fluid-solid reactions are represented by __________ model. (A) Continuous reaction (B) Unreacted core (C) Both (A) and (B) (D) Neither (A) and (B)
Last Answer : (C) Both (A) and (B)
Description : Do displacement reactions only occur between halogens?
Last Answer : Also other elements can be involved.
Description : Which one of the following aspects is an exclusive characteristic of living things? (a) Isolated metabolic reactions occur in vitro (b) Increase in mass from inside only (c) Perception of events ... memory. (d) Increase in mass by accumulation of material both on surface as well as internally
Last Answer : (d) Increase in mass by accumulation of material both on surface as well as internally.
Description : Metabolism is carried out by a large class of proteins that decrease the activation energy required for chemical reactions inside a cell. Therefore they only facilitate reactions that would naturally occur at a much slower rate. What is the name of these proteins that speed up biochemical reactions?
Last Answer : Enzymes
Description : Which of the following statements about the sales force in the 21st century is true? A. Sales managers will use a hands-off approach and let the professional salesperson be his or her own boss B ... touch E. All of the above statements about the sales force in the 21st century are true.
Last Answer : C. Sales management must be smart and nimble and provide technology-centered solutions to support the sales effort
Description : From the elements: Cl, Br, F, O, Al, C, Li, Cs and Xe; choose the following: (a) The element with highest negative electron gain enthalpy. (b) The element with lowest ionization enthalpy. ( ... . (f)The element which belongs to zero group. (g) The elements which forms largest number of compounds.
Last Answer : Ans. (a). The element chlorine (Cl) has the highest negative electron gain enthalpy. (b). The element cesium (Cs) has lowest ionization enthalpy. (c). The element fluorine F has lowest atomic radius. (d ... zero group (or group 18). (g). The element carbon (C) forms the largest number of compounds.
Description : Electrochemical corrosion can occur, only if __________ is present in contact with metal. (A) Air (B) Oxygen (C) Liquid medium (D) Gaseous medium
Last Answer : (C) Liquid medium
Description : Pick out the wrong statement. (A) In a batch reactor, which is exclusively used for liquid phase reactions; temperature pressure and composition may vary with time (B) In a semi-batch reactor, ... system (D) In a continuous flow reactor, both the reactants and the products flow out continuously
Last Answer : (C) In a continuous flow reactor, uniform concentration cannot be maintained throughout the vessel even in a well agitated system
Description : A batch reactor is suitable for (A) Achieving cent percent conversion of reactants into products (B) Large scale gaseous phase reactions (C) Liquid phase reactions (D) Obtaining uniform polymerisation products in highly exothermic reactions
Last Answer : (C) Liquid phase reactions
Description : A batch reactor is (A) Suitable for gas-phase reactions on commercial scale (B) Suitable for liquid phase reactions involving small production rate (C) Least expensive to operate for a given rate (D) Most suitable for very large production rate
Last Answer : (B) Suitable for liquid phase reactions involving small production rate
Description : Pick out the wrong statement. (A) Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point (B) Entropy of ... is negative for exothermic reactions (D) The eccentric factor for all materials is always more than one
Last Answer : (D) The eccentric factor for all materials is always more than one
Description : Steady state equimolal counter diffusion is encountered in (A) Separation of a binary mixture by distillation (B) Absorption of NH3 from air by water (C) All liquid-liquid diffusion systems (D) All liquid-solid diffusion systems
Last Answer : (A) Separation of a binary mixture by distillation
Description : Shrinkage allowance on pattern is provided to compensate for shrinkage when the (A) Metal changes from liquid state to solid state at freezing temperature (B) Solid phase temperature drops ... to room temperature (D) Liquid metal temperature drops from pouring temperature to freezing temperature
Last Answer : (B) Solid phase temperature drops from freezing temperature to the room temperature
Description : Density in the solid state is slightly less than that in its liquid state, in case of (A) Carbon dioxide (B) Water (C) Mercury (D) None of these
Last Answer : (B) Water
Description : an eutectic system, two elements are completely (A) Soluble in solid state (B) Insoluble in liquid state (C) Insoluble in both solid & liquid state (D) Soluble in liquid state
Last Answer : Option D
Description : Three pipes P, Q and R can fill a tank from empty to full in 40 minutes, 15 minutes, and 30 minutes respectively. When the tank is empty, all the three pipes are opened. P, Q and R discharge chemical solutions X, Y and Z respectively. ... 5 minutes? a) 8 / 15 b) 7 / 15 c) 8 / 17 d) 6 / 13 e) 8 / 13
Last Answer : a Part of the tank filled by pipe P in 1 minute = 1 / 40 Part of the tank filled by pipe Q in 1 minute = 1 / 15 Part of the tank filled by pipe R in 1 minute = 1/ 30 Here we have to find the proportion of ... together in 5 minute = 5 1/8 = 5/ 8 Required proportion = (1/3) / ( 5/8) = 8 / 15
Description : 3 faucet A,B,C can fill a cistern from empty to full in 45mins, 35mins, and 25 mins respectively. When the cistern is empty all the 3 faucets are opened. A,B,c discharge chemical solutions A,B,C respectively. What is ... the liquid in the tank after 5 mins? A) 63/143 B) 72/151 c) 67/173 D) 81/167
Last Answer : A Part filled by (A+B+C) in 5 mins = 5(1/45 +1/35 + 1/25) = 5 (35+45+63/1575) = 143/315 Part filled by c in 5 mins = 5/25 = 1/5 Required ratio = 1/5 * 315/143 =63/143.
Description : In which cell organelle do photo and thermochemical reactions occur in different sites ? -Do You Know?
Last Answer : answer:
Description : Which of the following reactions does not occur in Bessemer converter in the extraction of copper from chalcopyrites ?
Last Answer : Which of the following reactions does not occur in Bessemer converter in the extraction of copper from chalcopyrites ... 2Cu_(2)O rarr 6Cu + SO_(2)`
Description : Which one of the following reactions occur during smelting in the reduction zone at lower temperature(in iron metallurgy)?
Last Answer : Which one of the following reactions occur during smelting in the reduction zone at lower temperature(in iron ... CO` D. `CO_(2)+C rarr 2CO`
Description : Which one of the following reactions does not occur ?
Last Answer : Which one of the following reactions does not occur ? A. `BaO+O_(3)rarrBaO_(2)+O_(2)` B. `PbS+4O_(3)rarrPbSO_ ... (2)` D. `2Hg+O_(2)rarrHg_(2)O+O_(2)`
Description : Where in the chloroplast does light reactions of photosynthesis occur?
Last Answer : Light- independent reactions of photosynthesis occur in thestroma of the chloroplasts of a cell.
Description : What reactions occur in a cytoplasm?
Last Answer : What is the answer ?