Description : Consider the following statements: 1. The atmosphere of the primitive earth was reducing 2. The primary source of energy for the chemosynthetic reactions on earth that led to the origin of life was the solar energy 3. Liquid water did not ... 1 and 2 (b) 1 and 4 (c) 1, 2, and 3 (d) 1, 3, and 4
Last Answer : Ans:(d)
Description : Assertion (A) : Presently, the global atmosphere is warming up. Reason (R): The depletion of stratospheric ozone layer has resulted in increase in ult
Last Answer : Assertion (A) : Presently, the global atmosphere is warming up. Reason (R): The depletion of ... true but reason is wrong D. Both are wrong
Description : The atmosphere of the primitive earth before origin of life consisted of: (a) Nitrogen, Oxygen, Ammonia, and Water vapour (b) Methane, Ammonia, Hydrogen, and Water vapour (c) Nitrogen, Oxygen, Water, and Carbon dioxide (d) Ammonia, Water, Oxygen, and Hydrogen
Last Answer : Ans:(b)
Description : According to Oparin, which one of the following was not present in the primitive atmosphere of the earth? (a) Methane (b) Oxygen (c) Hydrogen (d) Water vapour
Last Answer : b) Oxygen
Description : Assertion :- Oxidation number of `Cr` in `CrO_(3)` is `+6`. Reason :- In `CrO_(5)`, four oxygen atoms are involved in peroxide linkage.
Last Answer : Assertion :- Oxidation number of `Cr` in `CrO_(3)` is `+6`. Reason :- In `CrO_(5)`, four ... Reason is False. D. If both Assertion & Reason are False.
Description : Peptizers like aromatic mercaptans (e.g. thiophenes) are added in rubber to (A) Protect rubber goods from attack by oxygen & ozone present in the atmosphere (B) Reduce its viscosity to ... processing (C) Reduce the time of vulcanisation and quantity of vulcanising agent (D) Increase its viscosity
Last Answer : (B) Reduce its viscosity to permit easier processing
Description : Primitive atmoshpere was reducing because:
Last Answer : Primitive atmoshpere was reducing because: A. Hydrogen atoms were few B. Hydrogen, atoms were active and ... atom were more D. Oxygen atoms were more
Description : Assertion :- `Cr^(+2)` is a reducing agent and `Mn^(+3)` is oxidising agent. Reason :- `Mn^(+3)` has `d^(5)` configuration.
Last Answer : Assertion :- `Cr^(+2)` is a reducing agent and `Mn^(+3)` is oxidising agent. Reason :- `Mn ... is False. D. If both Assertion & Reason are False.
Description : Assertion :- A reducing agent is a substance which accepts electron. Reason :- A substanc which helps in oxidaton is known as reducing agent.
Last Answer : Assertion :- A reducing agent is a substance which accepts electron. Reason :- A substanc which helps ... . D. If both Assertion & Reason are False.
Description : Assertion :- Nitrous acid `(HNO_(2))` may act as an oxidising agent as well as a reducing agent. Reason :- The oxidation number of Nitrogen remains sa
Last Answer : Assertion :- Nitrous acid `(HNO_(2))` may act as an oxidising agent as well as a reducing agent. ... False. D. If both Assertion & Reason are False.
Description : Assertion: Reaction of `SO_(2)` and `H_(2)S` in the presence of `Fe_(2)O_(3)` catalyst gives elemental sulphur. Reason: `SO_(2)` is a reducing agent.
Last Answer : Assertion: Reaction of `SO_(2)` and `H_(2)S` in the presence of `Fe_(2)O_(3)` catalyst gives ... is False. D. If both Assertion & Reason are False.
Description : Assertion: `SO_(3)` acts as an oxidising agent as well as a reducing agent Reason: `SO_(2)` acts as an oxidising as well as a reducing agent
Last Answer : Assertion: `SO_(3)` acts as an oxidising agent as well as a reducing agent Reason: `SO_(2)` acts as an oxidising as well as a reducing agent
Description : The ozone hole in the upper atmosphere of the earth is due to the breakdown of ozone to oxygen. The reaction is catalyzed by
Last Answer : The ozone hole in the upper atmosphere of the earth is due to the breakdown of ... D. chlorine formed by the decomposition of chlorofluorocarbons
Description : Why do scientists look for water vapor ozone or oxygen in a plants atmosphere?
Last Answer : Because they are interested in whether water vapor, ozone oroxygen in a plants atmosphere are there.
Description : The ultra violet radiations of the Sun do not reach the Earth because the upper layers of the atmosphere contain (a) oxygen (b) helium (c) ozone (d) hydrogen
Last Answer : Ans:(c)
Description : Ozone layer is formed due to reactions of : (1) oxygen and ultraviolet rays (2) carbon dioxide and layers of atmosphere (3) cosmic rays and layers of atmosphere (4) infrared rays and ultraviolet rays
Last Answer : (1) oxygen and ultraviolet rays Explanation: Ozone in the Earth's stratosphere is created by ultraviolet light striking ordinary oxygen molecules containing two oxygen atoms (O2), splitting them into ... (atomic oxygen). The atomic oxygen then combines with unbroken O2 to create ozone (O3).
Description : Ozone-hole in the atmosphere is largely caused by the presence of – (1) Oxygen (2) Hydrogen (3) Chlorofluorocarbons (4) Radio-active waste
Last Answer : (3) Chlorofluorocarbons Explanation: Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. It is calculated that a ... about a century, destroying up to one hundred thousand ozone molecules during that time.
Description : (1) the action of ultraviolet rays on oxygen Explanation: The majority of tropospheric ozone formation occurs when nitrogen oxides (NOx), carbon monoxide (CO ) and volatile organic compounds (VOCs), such as xylene, ... violet rays. NOx, CO, and VOCs are called ozone precursors. CO + 2O2 + CO2 + O3
Last Answer : Water is not effective in extinguishing a fire caused by petrol because - (1) the flame is too hot for water to cool it down (2) water and petrol react chemically (3) water and petrol are ... (4) water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn
Description : Ultra violet light of Sun's radiation is prevented from reaching the earth's atmosphere by the layer of – (1) Oxygen (2) Hydrogen (3) Ozone (4) Helium
Last Answer : (3) Ozone Explanation: The ozone layer is a layer in Earth's atmosphere containing relatively high concentrations of ozone (03). The layer absorbs 97-99% of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which potentially damages exposed life forms on Earth.
Description : In the atmosphere ultraviolet rays are absorbed by – (1) Oxygen (2) Nitrogen (3) Ozone (4) Helium
Last Answer : (1) Oxygen Explanation: Most of the ultraviolet radiation in sunlight is absorbed by oxygen in Earth's atmosphere, which forms the ozone layer of the lower stratosphere. UV light is found ... and causes many substances to glow or fluoresce. Most ultraviolet is classified as non-ionizing radiation.
Description : In upper layer of atmosphere ozone is formed by (1) the action of ultraviolet rays on oxygen (2) the combination of oxygen molecules (3) subjecting oxygen to high pressure (4) the action of nitrogen on oxygen in atmosphere
Last Answer : the action of ultraviolet rays on oxygen
Description : Ultra violet light of Sun’s radiation is prevented from reaching the earth’s atmosphere by the layer of (1) Oxygen (2) Hydrogen (3) Ozone (4) Helium
Last Answer : Ozone
Description : In the atmosphere ultraviolet rays are absorbed by (1) Oxygen (2) Nitrogen (3) Ozone (4) Helium
Last Answer : Oxygen
Last Answer : oxygen and ultraviolet rays
Description : Ozone-hole in the atmosphere is largely caused by the presence of (1) Oxygen (2) Hydrogen (3) Chloro-floro-carbon (4) Radio-active waste
Last Answer : Chloro-floro-carbon
Description : Assertion (A): UV radiation causes photodissociation of ozone into `O_(2)` and O, thus causing damage to the stratospheric change. Reason (R): Ozone h
Last Answer : Assertion (A): UV radiation causes photodissociation of ozone into `O_(2)` and O, thus causing damage ... true but reason is wrong D. Both are wrong
Description : Assertion: The O - O bond lengths in ozone molecule are intermediate between single and double bonds. Reason: `O_(3)` molecule is a resonance hybrid.
Last Answer : Assertion: The O - O bond lengths in ozone molecule are intermediate between single and double bonds. ... I is not correct and Statement-II is correct
Description : Assertion : In presence of ozone, mercury loses its meniscus and sticks to glasses. This is called tailing of mercury Reason: Tailing of mercury is du
Last Answer : Assertion : In presence of ozone, mercury loses its meniscus and sticks to glasses. This is called ... -I is not correct and Statement-II is correct
Description : Reducing assurance engagement risk to zero is very rarely attainable or cost beneficial as a result of the following factors, except a. The use of selective testing. b. The fact that much ... d. The use of judgment in gathering and evaluating evidence and forming conclusions based on that evidence
Last Answer : The practitioner may not have the required assurance knowledge and skills to gather and evaluate evidence.
Description : __________ Nature of hypo (sodium thiosulphate) makes it useful in photography. (A) Oxidising (B) Reducing (C) Complex forming (D) Photochemical
Last Answer : (C) Complex forming
Description : Assertion (A) : The concentration of methane in the atmosphere has more than doubled in the last 250 years. Reason (R): Wetlands and rice fields are t
Last Answer : Assertion (A) : The concentration of methane in the atmosphere has more than doubled in the last 250 ... true but reason is wrong D. Both are wrong
Description : Assertion : In Balanoglossus, proboscis is involved in excretion Reason : Glomerulus is present in proboscis.
Last Answer : Assertion : In Balanoglossus, proboscis is involved in excretion Reason : Glomerulus is present in ... . If both Assertion and Reason are false.
Description : Assertion:- Ribosomes are involved in protein synthesis. Reason:- They are membrane bound cell organelles.
Last Answer : Assertion:- Ribosomes are involved in protein synthesis. Reason:- They are membrane bound cell organelles. ... . If both Assertion & Reason are false.
Description : Assertion:- Mitochondria, chloroplast and peroxisome are not involved in endomembrane system. Reason:- Their functions are not coordinated with consti
Last Answer : Assertion:- Mitochondria, chloroplast and peroxisome are not involved in endomembrane system. Reason:- ... If both Assertion & Reason are false.
Description : The spectral region of the electromagnetic radiation which passes through the atmosphere without much attenuation is known as: (A) Ozone hole (B) Atmospheric window (C) Ozone window (D) Black hole
Last Answer : Answer: Option B
Description : In which of the following ozone acts as reducing agent?
Last Answer : In which of the following ozone acts as reducing agent? A. `BaO_(2)+O_(3)rarrBaO+2O_(2)` B. `2HCl+O_(3) ... . `2KI+O_(3)+H_(2)Orarr2KOH+I_(2)+O_(2)`
Description : The Kyoto Protocol is for a. limiting Green house gases b. Ozone depleting substance c. Reducing acid rain d. None of the above
Last Answer : a. limiting Green house gases
Description : Assertion `:` Myocardial infarction oftern results from a sudden decrease in coronary blood supply resulting in decreased oxygen supply. Reason `:` Th
Last Answer : Assertion `:` Myocardial infarction oftern results from a sudden decrease in coronary blood supply ... If both Assertion & Reason are false.
Description : Assertion `:` Lymph is the filtered blood from capillaries, which is rich in oxygen, but devoid of RBC. Reason `:` RBC can filter out due to small dia
Last Answer : Assertion `:` Lymph is the filtered blood from capillaries, which is rich in oxygen, but devoid of RBC ... . D. If both Assertion & Reason are false.
Description : Assertion `:-` Low concentration of oxygen allow dissociation of oxyhaemoglobin. Reason `:-` CO has more affinity with Haemoglobin as compares to oxyg
Last Answer : Assertion `:-` Low concentration of oxygen allow dissociation of oxyhaemoglobin. Reason `:-` CO has more ... D. If both Assertion & Reason are false.
Description : Assertion `:-` Haemoglobin can not get saturated with oxygen more than `97%`. Reason `:-` With a rise in `PO_(2)`, the affinity between `O_(2)` & haem
Last Answer : Assertion `:-` Haemoglobin can not get saturated with oxygen more than `97%`. Reason `:-` With a ... False. D. If both Assertion & Reason are false.
Description : Assertion `:-` While ascending up a mountain , one gets less oxygen resulting in hypoxia. Reason `:-` Percentage of oxygen decreases in the air at hig
Last Answer : Assertion `:-` While ascending up a mountain , one gets less oxygen resulting in hypoxia. Reason `:- ... . D. If both Assertion & Reason are false.
Description : Assertion:- In MgO electrovalency of Mg is 2. Reason :- Mg shares two electrons with oxygen.
Last Answer : Assertion:- In MgO electrovalency of Mg is 2. Reason :- Mg shares two electrons with oxygen. A. If ... False. D. If both Assertion & Reason are false
Description : Assertion: The enthalpy of formation of gaseous oxygen molecules at `298K` and under1 atm is zero. Reason: The entropy of formation of gaseous oxygen
Last Answer : Assertion: The enthalpy of formation of gaseous oxygen molecules at `298K` and under1 atm is zero. ... D. If both Assertion & Reason are false.
Description : Assertion: Bond angle at oxygen in ethehers is greater than ideal tetrahedral angle Reason: Stearic hindrance between alkyl groups increase bond angle
Last Answer : Assertion: Bond angle at oxygen in ethehers is greater than ideal tetrahedral angle Reason: Stearic ... D. Assertion is false, Reason is true
Description : Assertion (A): Alkyl aryl ethers on reaction with HI give alkyl iodide phenols Reason (R): Aryl - oxygen bond is weaker than alkyl oxygen bond
Last Answer : Assertion (A): Alkyl aryl ethers on reaction with HI give alkyl iodide phenols Reason (R): Aryl - oxygen ... is false D. A is false but R is true
Description : Assertion (A) Both rhombic and monoclinic sulphur exist as `S_(8)` but oxygen exists as `O_(2)`. Reason (R ) Oxygen forms `ppi-ppi` multiple bond due
Last Answer : Assertion (A) Both rhombic and monoclinic sulphur exist as `S_(8)` but oxygen exists as `O_ ... Statement-I is not correct and Statement-II is correct
Description : Assertion :- Bromide ion is serving as a reducing agent in the reaction `2MnO_(4)^(-)(aq.)+Br^(-)(aq.)+H_(2)Orarr2MnO_(2)(aq.)+BrO_(3)^(-)(aq.)+2OH^(-
Last Answer : Assertion :- Bromide ion is serving as a reducing agent in the reaction `2MnO_(4)^(-)(aq.)+Br^( ... is False. D. If both Assertion & Reason are False.
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.