Aman Yadav Dropper Sample

Nobody is wrong. Check the temperatures. NCERT uses 298 K to 308 K. Compute: $$E_a = 2.303\times8.314\times\log 2\times\frac{298\times308}{10} = 5.763\times9178 \approx 52.9\ \text{kJ/mol}$$ Yours: 300 and 310: $5.763\times\frac{300\times310}{10} = 5.763\times9300 \approx 53.6$ kJ/mol. Same method, different temperatures. The point is that $E_a$ around 50 kJ/mol gives a doubling near room temperature. It's not an exact law, just a rule of thumb.

3d ago

On usefulness for JEE. Directly, almost none. They give limits to compute, not to prove. Indirectly it helps you understand continuity and differentiability questions, because those are defined with limits. One evening on it is fine. Don't spend a week.

4d ago

Iodoform rule. Positive if the compound has $CH_3CO-$ (methyl ketone or ethanal) or $CH_3CH(OH)-$ (ethanol, propan-2-ol, and other secondary alcohols with methyl on the carbinol carbon). Methanol: no. Acetic acid: no. Pentan-3-one: no, both sides are ethyl. Yellow ppt, antiseptic smell. Another test to know: 2,4-DNP reagent gives an orange-yellow precipitate with both aldehydes and ketones. That separates carbonyls from alcohols and acids.

4d ago

Ethers. Name as alkoxy alkane. Smaller alkyl group goes with oxygen as alkoxy, the larger is the parent chain. $CH_3OC_2H_5$: methoxyethane. $C_6H_5OCH_3$: methoxybenzene, anisole. $C_6H_5OC_2H_5$: ethoxybenzene, phenetole. Primary/secondary/tertiary: count the carbons attached to the carbon carrying OH. Mono/di/tri: count OH groups. Different questions, different counting.

5d ago

The last point is correct. Hacks that feel good are fake. Hacks that feel annoying are real. Active recall. Do the question again. No shortcuts.

5d ago

Exam tip. Fill by $(n + l)$: lower value first. If equal, lower $n$ first. 4s: 4 + 0 = 4. 3d: 3 + 2 = 5. So 4s first. But for ions: lose electrons from highest $n$ first. 4s before 3d. This is a rule, memorise it. Also: Cu⁺ = $3d^{10}$, Cu²⁺ = $3d^9$ (1 unpaired, coloured). Zn²⁺ = $3d^{10}$ (colourless).

5d ago

The denominator one. Everyone should know this. 2 to 3 is 50 per cent. Good example.

6d ago

I overworked too. Result: dropped my mocks. Slept more, scores up. Do not be proud of ten hours. Be proud of ten good hours.

7d ago

Branch vs college: depends on what you want after. If you want to code, the branch matters less. If you want core engineering, branch matters more. Decide what you want at 22 first. Then check which option gets you closer. Also ask the B college for last year's real placement data, including median, not the poster.

7d ago

DDT. First chlorinated organic insecticide, very effective against mosquitoes and crop pests. Problem: it is not metabolised by the animal body, gets stored in fatty tissues and moves up the food chain. Banned in many countries for agricultural use. That is what NCERT wants.

9d ago

Good rule. Decision removal is what works. Willpower is a bad system. I stopped fighting myself in the same way. Fixed slots, no debate.

9d ago

Smog table, learn this and you're done: | | Classical (London) | Photochemical (Los Angeles) | |---|---|---| | Weather | cool, humid | warm, dry, sunny | | Made from | smoke + fog + $SO_2$ | NOx + hydrocarbons + sunlight | | Nature | reducing smog | oxidising smog | | Occurs | winter, early morning | summer, midday | | Key products | sulphur compounds, smoke | $O_3$, PAN, HCHO, acrolein | Reactions for the photochemical one: $NO_2 \xrightarrow{h\nu} NO + O$ $O + O_2 \rightarrow O_3$ $NO + O_3 \rightarrow NO_2 + O_2$ Then hydrocarbons react with ozone and NO to give formaldehyde, acrolein and PAN (peroxyacetyl nitrate).

9d ago

Normal. In an indefinite integral the +C is part of the answer. No C, no full marks. Put it in the last line of every indefinite integral. Habit.

10d ago

Time of flight also differs. For θ and 90°−θ: $T_1 = \frac{2u\sin\theta}{g}$, $T_2 = \frac{2u\cos\theta}{g}$, so $\frac{T_1}{T_2} = \tan\theta$. And $T_1 T_2 = \frac{2R}{g}$, which shows up in some questions. Only the horizontal range is shared.

10d ago

Formation conditions from NCERT, as I remember them: - $XeF_2$: Xe in excess + $F_2$, 673 K, 1 bar - $XeF_4$: Xe : $F_2$ = 1 : 5, 873 K, 7 bar - $XeF_6$: Xe : $F_2$ = 1 : 20, 573 K, 60–70 bar Notice that more fluorine and higher pressure gives higher fluoride. Hydrolysis of $XeF_6$ gives $XeO_3$: $XeF_6 + 3H_2O \rightarrow XeO_3 + 6HF$. Partial hydrolysis gives $XeOF_4$.

13d ago

Try this. Suppose the gap between 0.999... and 1 is some positive number g. Pick n big enough that $1/10^n < g$. But 0.99...9 with just n nines is already within $1/10^n$ of 1, and 0.999... is at least that close. So the actual gap is smaller than g. Contradiction. So g can't be positive. It's zero.

13d ago

Anime is fiction. Real discipline is boring. No soundtrack, no rival. But your point about mistake analysis is right. That is the only thing that moved my rank too. 45 min per mock is a good number.

13d ago

Wrong. Liquids: viscosity decreases as temperature rises. Molecules gain enough energy to overcome the attraction to neighbours, so they flow easier. That's why honey pours faster when warm. Surface tension also decreases with temperature. Gases are the opposite: viscosity rises with temperature. Vapour pressure of liquids rises with temperature.

14d ago

Agree with this. Boards: do the writing blocks, don't skip. Entrance: daily. Both: NCERT first.

14d ago

Good habit. In the exam hall I do dimensions on every second step. Costs nothing. Saved me 4 marks in my last test.

15d ago

Simple. $V = 0$ does not imply $E=0$. $E = 0$ does not imply $V = 0$ either. Inside a charged conducting shell, E is zero but V equals the surface value. Learn both examples, NEET asks it as a statement type question.

16d ago

Correct. Quality over time. 20 good seconds beats 60 bad ones.

16d ago

Good addition. Leg swings are fine. Keep stretches gentle, no bouncing.

17d ago

No. See "too much". You will be in pain for a week. Start with 5 to 8 clean ones. Add slowly.

17d ago

Same plan. Muscles do not know who owns them. Start from the easier versions if needed and progress the same way.

17d ago

Understood. Got it wrong. Corrected in notes.

17d ago

Priestley is the one who found oxygen comes from CO2. Ingenhousz found it was water. Short version.

17d ago

Ask the friend, but ask in a better way. Not "how to solve?" Ask "what is the first thing you would try?" Then post the problem on a forum for students, write your 20 minutes of attempt, people help more when you show work. Also an answer-only book is still useful. Get the answer, then work backward to see if you can reach it.

19d ago

No. 2I = π/2 means I = π/4. Divide by two. Check by estimating: the integrand goes from 0 to 1 over a length of about 1.57, so the answer should be less than 1.57. π/2 is exactly 1.57, so impossible. π/4 is about 0.79, sensible.

19d ago

Same thing. $v = R\omega$, so $dv/dt = R\,d\omega/dt = R\alpha$. Two ways to write the same $a_t$. Use whichever the question gives you.

19d ago