Description : Silver halides are used in photographic plates because they are - (1) oxidised in air (2) soluble in hyposolution (3) reduced by light (4) totally colourless
Last Answer : (3) reduced by light Explanation: The light-sensitive chemicals used in photographic film and paper are silver halides. Silver halides are used in photographic film and photographic paper, including ... - meaning that it can undergo development which turns the entire crystal into metallic silver.
Description : Silver halides are used in photographic plates because they are (a) Oxidised in air (b) Colourless (c) Easily soluble in a hypo solution (d) Readily reduced by light
Last Answer : Ans:(d)
Description : Photographic plates are covered with black paper because (a) the cellulose acetate of the paper must remain fresh (b) sunlight is easily absorbed by black paper and it helps develop the film ... paper prevents contact with light (d) the conversion of silver bromide to metallic silver is essential
Last Answer : Ans:(c)
Description : Photographic plates are coated with (A) Silver nitrate (B) Silver halide (C) Calcium silicate (D) Metallic silver
Last Answer : (B) Silver halide
Description : Winch of the following is not true about X-rays? (1) have low penetrating power (2) travel with the speed of light (3) Can be reflected or refracted (4) can affect photographic plates
Last Answer : (1) have low penetrating power Explanation: X-rays and gamma rays are photons, i.e. high-energy light-waves. When emitted by a source, for example, radium or cobalt, located outside the body, they ... they can be used in diagnostic medicine to image human bones or human organs made opaque by a dye.
Description : Which of the following is not true about X-rays? (1) have low penetrating power (2) travel with the speed of light (3) Can be reflected or refracted (4) can affect photographic plates
Last Answer : have low penetrating power
Description : The chemical used in developing photographic films is – (1) silver bromide (2) hypo (3) sodium sulphate (4) hydroquinone
Last Answer : (1) silver bromide Explanation: Tritium is a radioactive isotope of hydrogen. It is the lightest radioactive element.
Description : Which halide is used in making sensitive emulsion on photographic film? (1) Sodium chloride (2) Silver bromide (3) Silver iodide (4) Silver chloride
Last Answer : (2) Silver bromide Explanation: Silver bromide, a soft, paleyellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials.
Description : The chemical used in developing photographic films is (1) silver bromide (2) hypo (3) sodium sulphate (4) hydroquinone
Last Answer : silver bromide
Description : A colourless water-soluble compound on strong heating liberates a brown colored gas and leaves a yellow residue that turns white on cooling. An aqueou
Last Answer : A colourless water-soluble compound on strong heating liberates a brown colored gas and leaves a yellow residue that turns ... (3))_(3)` D. `NaNO_(3)`
Description : Which one of the following metals is immune to corrosion by air, water, hydrochloric acid and nitric acid; but is soluble in aqua regia? w) gold x) silver y) magnesium z) nickel
Last Answer : ANSWER: W -- GOLD
Description : Function of sodium thiosulphate (hypo) in development of photographic film/plate is to (A) Brighten the faint images (B) Remove metallic silver (C) Convert silver chloride to silver (D) Remove unexposed silver halide
Last Answer : (D) Remove unexposed silver halide
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 : 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 : Assertion :- `H_(2)S+Cl_(2)rarr2HCl+S` In the above reaction, Cl has been oxidised to `Cl^(-)` while `S^(-2)` has been reduced to S Reason :- In a rea
Last Answer : Assertion :- `H_(2)S+Cl_(2)rarr2HCl+S` In the above reaction, Cl has been oxidised to `Cl^(-)` ... is False. D. If both Assertion & Reason are False.
Description : When iron is rusted, it is (A) Converted to a fine powder (B) Reduced (C) Oxidised (D) None of these
Last Answer : (C) Oxidised
Description : What happens when a substance loses oxygen during reaction? It is said to be (a) Oxidised (b) Reduced (c) Both (d) None of the above
Last Answer : (b) Reduced
Description : What happens when a substance gains oxygen during reaction? The substance gets – (a) Oxidised (b) Reduced (c) Both oxidized and reduced (d) None of the above
Last Answer : (a) Oxidised
Description : All noble gases are - (1) Colourless (2) Odourless (3) Colourless and Odourless (4) Light blue
Last Answer : (3) Colourless and Odourless Explanation: Other characteristics of the noble gases are that they all conduct electricity, fluoresce, are odorless and colorless, and are used in many conditions when a stable element is needed to maintain a safe and constant environment.
Description : Which of the following compounds is ONLY WEAKLY soluble in cold water? w) Silver Nitrate x) Sodium Carbonate y) Sodium Chloride z) Lead Chloride
Last Answer : ANSWER: Z -- LEAD CHLORIDE
Description : 7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated
Last Answer : A) hysteresis losses is reduced
Description : The following are true about the lens: a. it has a higher concentration of sodium than potassium b. it has the highest concentration of protein than other organs in the body c. 90% of proteins in the lens are water-soluble d. gluthatione is reduced in cataract
Last Answer : gluthatione is reduced in cataract
Description : An aluminium strip is kept immersed in a freshly prepared ferrous sulphate solution taken in a test tube, the change observed is that a) Green solution slowly turns brown b) Lower end of the test ... c)A colourless gas with smell of burning sulphur is evolved c)Light green solution changes to blue
Last Answer : a) Green solution slowly turns brown
Description : Do you wash plates and silver ware with hot water and soap no matter what they were used for?
Last Answer : Yes. It’s wasteful of time, water and energy, but if a dish/glass knife was put “out” then it needs to be re-washed before it can go back in the drawer. I never claimed to be perfect.
Description : Why the presence of a base is essential in the ammonolysis of alkyl halides ?
Last Answer : During ammonolysis of alkyl halides, the acid liberated during the reaction combines with the amine formed to form amine salt. To liberate free amine from the amine salt, a base is needed.
Description : Metal sulphides occur mainly in rocks and metal halides in lakes and seas. Explain.
Last Answer : Ans.: Metal halides being soluble in water, get dissolved in rain water and are carried to lakes and seas during weathering of rocks. On the otherhand, metal sulphides being insoluble are left behind in the rocks as residue.
Description : Give reason for the appearance of colour in alkali metal halides.
Last Answer : Due to F-centres.
Description : When ammonia is added to an alkyl halide, in the presence of base : (a) primary amines form (b) amides form (c) nitrated alkyl halides form (d) quaternary ammonium salts form
Last Answer : primary amines form
Description : Aryl halides are less reactive towards nucleophilic substitution as compared to alkyl halides due to (a) Inductive effect (b) Resonance stabilization (c) Tautomerism (d) Stereoisomerism
Last Answer : Resonance stabilization
Description : Alkyl halides react with ammonia in the presence of base to form : (a) primary amines (b) nitrated alkyl halides (c) amides (d) quaternary ammonium salts
Last Answer : primary amines
Description : Grignard reagents do not show any reaction with (a) Alkoxyalkanes (b) Alkanones (c) Alkyl alkanoates (d) Acyl halides
Last Answer : Alkoxyalkanes
Description : Which of the following halides is least reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2Cl
Last Answer : (CH3)3CCH2I
Description : Which of the following halides is most reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2C
Last Answer : (CH3)2CHCHICH3
Description : Which of the following statements concerning SN2 reactions of alkyl halides is not correct? (a) The rate of reaction depends on the concentration of the nucleophile. (b) The rate of reaction depends on the ... carbon of the C-Br bond. (d) All alkyl iodides react more rapidly than all alkyl chlorides
Last Answer : All alkyl iodides react more rapidly than all alkyl chlorides
Description : Which of the following is not correct concerning substitution and elimination reactions of alkyl halides? (a) The electrophile replaces the leaving group. (b) Compounds containing electron-donating groups bonded to an ... replaced by another atom or group in substitution reactions. (d) (a) and (b)
Last Answer : (a) and (b)
Description : Which alkyl halides react most readily by nucleophilic substitution? (a) CH3CH2Cl (b) CH3CH2I (c) CH3CH2Br (d) CH3CH2F
Last Answer : CH3CH2I
Description : Alkyl halides undergo (a) Electrophilic substitution reactions (b) Electrophilic addition reactions (c) Nucleophilic substitution reactions (d) Nucleophilic addition reactions
Last Answer : Nucleophilic substitution reactions
Description : Whose name is given to alkylmagnesium halides: w) Victor Grignard x) Daniel Rutherford y) Dmitri Mendeleev
Last Answer : ANSWER: W -- VICTOR GRIGNARD
Description : Compounds of iodine are NOT used for which of the following? w) as a refrigerant x) in photographic film y) as an essential part of diet z) as an antiseptic
Last Answer : ANSWER: W -- AS A REFRIGERANT
Description : Gold; Silver and Platinum are soluble in?
Last Answer : 3:1
Description : When charging lead-acid batteries, the charging rate should be reduced as the battery nears its full charge to ____________. A. prevent damaging battery plates B. allow equalization of cell voltages C. reduce lead sulfate deposits D. increase lead peroxide formation
Last Answer : Answer: A
Description : Pick out the wrong statement. (A) Benzopyrene which causes cancer is present in traces in tobacco, charcoal & petrol driven automobile exhaust (B) NO2 is capable of penetrating the troposphere and ... at all produced during combustion of sulphur bearing fuels as all the sulphur is oxidised to SO2
Last Answer : (D) H2S is not at all produced during combustion of sulphur bearing fuels as all the sulphur is oxidised to SO2
Description : Iron is not used alone as a catalyst in ammonia synthesis, because (A) Its activity declines rapidly, if heated to above 520°C (B) It decomposes ammonia (C) It gets oxidised above 500°C (D) None of these
Last Answer : (A) Its activity declines rapidly, if heated to above 520°C
Description : Steels with high carbon equivalent have poor Weldability, because in these steels during welding (A) Carbon and other alloying elements get oxidised from the weld pool (B) Excessive ferrite forms in the ... of carbon and other element occurs in the weld pool leading to poor properties of the weld
Last Answer : (C) Martensite forms in the heat affected zone leading to poor toughness/ductility of the weld
Description : The plates of a NiCad storage battery are made of ________. A. potassium hydroxide with a small amount of sulfuric acid B. lead and lead peroxide C. silver oxide and lead sulfate D. combinations of nickel powder and nickel & cadmium salts
Last Answer : Answer: D
Description : (3) prevents freezing of petrol Explanation: Ethylene glycol (IUPAC name: ethane-1,2-diol) is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is ... A mixture of 60% ethylene glycol and 40% water freezes at -45 degree C (- 49 degree F).
Last Answer : Rust is - (1) A mixture of Fe₂O₃ and Fe(OH) ₂ (2) A mixture of FeO and Fe(OH)₂ (3) FeO only (4) A mixture of Fe₂O₃, 3H₂O and FeO
Description : Which of the following is Colourless? (1) Chlorine (2) Oxygen (3) Phosphorus (4) Sulphur
Last Answer : (2) Oxygen
Description : Acids turn blue litmus into which color? (1) Green (2) Red (3) Pink (4) Colourless
Last Answer : (2) Red Explanation: Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F).
Description : On passing H2 S through dilute HNO3 the colourless solution becomes turbid. Why ?
Last Answer : Ans. Due to formation of colloidal sol of Sulphur.