IIT JEE Practice Question and Answer
8Q: What has a neck but no head and wears a cap? 1579 05b5cc697e4d2b4197774c5d5
5b5cc697e4d2b4197774c5d5- Show AnswerHide Answer
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Answer :
Explanation :
A bottle has a neck but no head and wears a cap.
Q: Which of the following is the strongest acid? 1578 05b5cc6b7e4d2b4197774d5ec
5b5cc6b7e4d2b4197774d5ec- 1ClCH2COOHfalse
- 2BrCH2COOHfalse
- 3FCH2COOHtrue
- 4ICH2COOHfalse
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Answer : 3. "FCH2COOH"
Explanation :
Answer: C) FCH2COOH Explanation: FCH2COOH is the strongest acid out of all .Since the electron withdrawing inductive effect (-I effect) of the halogens decreases in the order F>Cl> Br> I , therefore the acidic strength of the α- halo acids decreases in the same order. FCH2COOH > ClCH2COOH > BrCH2COOH > ICH2COOH.
Q: If 2 men and 3 women can do a piece of work in 8 days and 3 men and 2 women in 7 days. In how many days can the work be done by 5 men and 4 women working together? 1578 05b5cc6bde4d2b4197774d924
5b5cc6bde4d2b4197774d924- 13 daysfalse
- 26 daysfalse
- 34 daystrue
- 42 daysfalse
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Answer : 3. "4 days"
Explanation :
Answer: C) 4 days Explanation: From the given data, => (2 M + 3W) 8 = (3M + 2W)7 => 16M + 24W = 21M + 14 W => 10W = 5M => 2W = M => 14W × ? = 7W × 8 ? = 4 days
Q: What is the conjugate base of H2O? 1577 05b5cc63de4d2b4197774baf9
5b5cc63de4d2b4197774baf9- 1NH3+false
- 2OH-true
- 3H2Ofalse
- 4All the abovefalse
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Answer : 2. "OH-"
Explanation :
Answer: B) OH- Explanation: A conjugate acid, is a species formed by the reception of a proton (H+) by a base—in other words, it is a base with a hydrogen ion added to it. On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid. Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic. Represented as the following chemical reaction: Acid + Base ⇌ Conjugate Base + Conjugate Acid The water molecule is the conjugate acid of the hydroxide ion after the latter received the hydrogen proton donated by ammonium. On the other hand, ammonia is the conjugate base for the acid ammonium after ammonium has donated a hydrogen ion towards the production of the water molecule. We can also refer to OH- as a conjugate base of H2O, since the water molecule donates a proton towards the production of NH+4 in the reverse reaction, which is the predominating process in nature due to the strength of the base NH3 over the hydroxide ion.
Q: At what temperature do pathogenic bacteria grow best in food? 1577 05b5cc6ade4d2b4197774d134
5b5cc6ade4d2b4197774d134- 15 to 15 degrees Celsiusfalse
- 215 to 25 degrees Celsiusfalse
- 320 to 45 degrees Celsiustrue
- 440 to 65 degrees Celsiusfalse
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Answer : 3. "20 to 45 degrees Celsius"
Explanation :
Answer: C) 20 to 45 degrees Celsius Explanation: The Bacteria that causes Food Borne illness are called Food Borne Pathogens. Most of the pathogens are mesophilic in nature, optimum temperature may be around 20-45 degree celsius. This range of temperatures is often called the "Danger Zone." Dry foods do not support the growth of bacteria. In order to kill pathogenic bacteria you need temperatures above 74ºC. Temperature is the easiest factor to control in order to prevent bacterial growth.
Q: What is the most commonly spoken language in the world? 1577 05b5cc69ae4d2b4197774c773
5b5cc69ae4d2b4197774c773- 1Mandarin Chinesetrue
- 2Englishfalse
- 3Spanishfalse
- 4Hindifalse
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Answer : 1. "Mandarin Chinese"
Explanation :
Answer: A) Mandarin Chinese Explanation:
Q: Electron configuration of cobalt 2+? 1577 05b5cc69be4d2b4197774c7c7
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Answer :
Explanation :
The electron configuration for Cobalt at ground state would simply be Co: [Ar] 4s23d7. The s,p,d,f configuration for cobalt (Co) is 1s22s22p63s23p64s23d7 , determined by the position of the element on the periodic table. Cobalt is an inner transition metal which means the electron configuration will end in d block. Cobalt is in the 7th column of the d block and therefore has 7 d electrons d7.
Q: The term biodiversity refers to 1576 05b5cc662e4d2b4197774beac
5b5cc662e4d2b4197774beac- 1Range of genetic variation within a populationfalse
- 2Total number of different species within a habitatfalse
- 3Both A & Btrue
- 4None of the abovefalse
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Answer : 3. "Both A & B"
Explanation :
Answer: C) Both A & B Explanation: The term biodiversity refers to the variety of life on Earth at all its levels, from genes to ecosystems, and the ecological and evolutionary processes that sustain it.

