CHEMOXY CLASSES

Dear Students,

The Re-NEET date is expected to be announced soon.

As seen in 2024, the Re-NEET paper was quite tricky and included many questions from learning-based portions such as: • d & f Block Elements
• Structure Determination
• Organic Qualitative Analysis
• and other NCERT-focused topics.

I strongly recommend downloading and analyzing the 2024 Re-NEET paper carefully.

At this stage, your focus should be completely on preparation: • Don’t waste time in unnecessary discussions.
• Don’t seek sympathy or get trapped in self-pity.
• Stay calm, stay focused, and keep studying consistently.

Your hard work during this phase will decide your result.

If you want revision sessions on any topic, feel free to connect anytime.

Study hard. Stay disciplined.

Thank You
Chemoxy Classes

1 month ago | [YT] | 9

CHEMOXY CLASSES

Chemical Kinetics Full Course | JEE Main, Advanced, NEET & Olympiad Chemistry 🚀: www.youtube.com/playlist?list...

Complete Chemical Kinetics is Uploaded for any Exam you are preparing for.
These lectures are not for fun only serious candidates come and make proper notes.
I assure , you will be able to solve any question after this

Thankyou
Chemoxy Classes

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2 months ago | [YT] | 6

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🧪 OXIDATION NUMBER / OXIDATION STATE
✨ Chemoxy Classes | IIT-JEE • NEET • Olympiad

--------------------------------------------------

🔹 What is Oxidation Number?
Oxidation number (O.N.) is the hypothetical charge an atom would have if all bonds were completely ionic.

👉 Uses:
• Identify oxidation and reduction
• Balance redox reactions
• Important for electrochemistry & inorganic chemistry

--------------------------------------------------

🔹 Basic Rules to Calculate Oxidation Number

1. Free Element:
O.N. = 0
Example: H2, O2, N2, Cl2

2. Monoatomic Ion:
O.N. = Charge on ion
Example: Na⁺ = +1, Cl⁻ = –1, Fe³⁺ = +3

3. Oxygen:
Usually = –2
Exceptions:
• Peroxide (H2O2) = –1
• Superoxide (KO2) = –1/2
• OF2 = +2

4. Hydrogen:
Usually = +1
Exception:
• Metal hydrides (NaH, CaH2) = –1

5. Alkali Metals (Group 1):
Always = +1

6. Alkaline Earth Metals (Group 2):
Always = +2

7. Fluorine:
Always = –1

8. Sum Rule:
• In neutral compound → Sum of O.N. = 0
• In ion → Sum = charge on ion

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🔹 Important Examples

Example 1: H2O
Let O.N. of O = x
2(+1) + x = 0
x = –2

Example 2: H2O2 (Peroxide)
2(+1) + 2x = 0
x = –1

Example 3: NH3
x + 3(+1) = 0
x = –3

Example 4: H2SO4
2(+1) + x + 4(–2) = 0
x = +6

Example 5: KMnO4
(+1) + x + 4(–2) = 0
x = +7

Example 6: K2Cr2O7
2(+1) + 2x + 7(–2) = 0
x = +6

Example 7: NO3⁻
x + 3(–2) = –1
x = +5

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🔹 Shortcut Tricks (Very Important for NEET)

🔥 Oxygen mostly = –2
🔥 Hydrogen mostly = +1
🔥 Total sum = charge rule ALWAYS apply
🔥 Learn common oxidation states:
• Mn = +2, +4, +7
• Cr = +3, +6
• S = –2, +4, +6
• N = –3 to +5

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🔹 Oxidation vs Reduction

Oxidation:
• Increase in oxidation number
• Loss of electrons

Reduction:
• Decrease in oxidation number
• Gain of electrons

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🔹 Example (Redox Reaction)

Zn + Cu²⁺ → Zn²⁺ + Cu

Zn: 0 → +2 (Oxidation)
Cu: +2 → 0 (Reduction)

👉 Zn = Reducing Agent
👉 Cu²⁺ = Oxidizing Agent

--------------------------------------------------

🔹 Most Important Exam Points

⭐ Sum rule is the key
⭐ Exceptions are frequently asked
⭐ Practice ions & complex compounds
⭐ Focus on PYQs (very important for NEET)

--------------------------------------------------

📌 Chemoxy Classes Tip:
“Oxidation Number is scoring + conceptual — master rules & practice daily to gain full marks in NEET.”

🚀 Follow Chemoxy Classes for more high-quality Chemistry content!

3 months ago | [YT] | 6

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🔥 THERMODYNAMICS FORMULA SHEET (NEET 2026) 🔥
📢 Chemoxy Classes | Subscribe for Concept Clarity 🚀

🧪 1. BASIC DEFINITIONS

✔ Internal Energy (U)
✔ Heat (q), Work (w)

👉 First Law:
ΔU = q + w

⚙️ 2. WORK FORMULAS

✔ Work (general):
w = –PΔV

✔ Isothermal (ideal gas):
w = –nRT ln(V₂/V₁)

✔ Adiabatic:
w = (P₁V₁ – P₂V₂)/(γ – 1)

🌡️ 3. HEAT RELATIONS

✔ q = mCΔT
✔ q = nCₘΔT

✔ At constant volume:
qᵥ = ΔU

✔ At constant pressure:
qₚ = ΔH

🔥 4. ENTHALPY (H)

✔ H = U + PV
✔ ΔH = ΔU + Δ(PV)

👉 Ideal Gas:
ΔH = ΔU + ΔnRT

⚡ 5. HEAT CAPACITY

✔ C = q/ΔT
✔ Cp – Cv = R

✔ γ = Cp/Cv

💨 6. IDEAL GAS RELATIONS

✔ PV = nRT
✔ ΔU = nCᵥΔT
✔ ΔH = nCₚΔT

❄️ 7. ADIABATIC PROCESS

✔ TV^(γ–1) = constant
✔ PV^γ = constant
✔ T^γ P^(1–γ) = constant

🔁 8. ISOTHERMAL PROCESS

✔ PV = constant
✔ ΔU = 0
✔ q = –w

⚖️ 9. ENTHALPY CHANGES

✔ ΔH = ΣH(products) – ΣH(reactants)

👉 Hess’s Law:
ΔH(total) = sum of steps

👉 Bond Enthalpy:
ΔH = Σ(Bonds broken) – Σ(Bonds formed)

⚡ 10. ENTROPY (S)

✔ ΔS = q_rev / T

👉 For ideal gas:
ΔS = nR ln(V₂/V₁)

🎯 11. GIBBS FREE ENERGY

✔ G = H – TS
✔ ΔG = ΔH – TΔS

👉 Spontaneity:
ΔG < 0 → spontaneous

👉 Relation:
ΔG = –RT lnK

⚖️ 12. EQUILIBRIUM LINK

✔ ΔG° = –RT lnK

💡 EXAM TRICKS

✔ Isothermal → ΔU = 0
✔ Adiabatic → q = 0
✔ Cp > Cv always
✔ ΔG negative → spontaneous

📌 Save this for revision 🔁
💬 Comment “THERMO DONE” if you completed it
🚀 Chemoxy Classes | Your JEE/NEET Mentor

3 months ago | [YT] | 8

CHEMOXY CLASSES

🔥 REIMER–TIEMANN REACTION – Complete Quick Notes (JEE/NEET/Olympiad) 🔥

📌 Definition:
When phenol (C₆H₅OH) reacts with CHCl₃ + NaOH (aq) → it forms o-hydroxybenzaldehyde (Salicylaldehyde)

📌 General Reaction:
Phenol + CHCl₃ + 3NaOH → o-Hydroxybenzaldehyde + 3NaCl + 2H₂O

🧠 Mechanism (Very Important):

CHCl₃ + OH⁻ → :CCl₂ (Dichlorocarbene ⚡)

Electrophilic attack on phenol ring (o-/p-position)

Hydrolysis → –CHO group formed

📍 Key Points:
✔ –OH group activates ring → ortho & para directing
✔ Major product = Ortho (due to intramolecular H-bonding)
✔ Para product = Minor

❗ EXCEPTIONS & SPECIAL CASES (VERY IMPORTANT):

🚫 If para position is blocked → Only ortho product forms

🚫 If both ortho positions blocked → Reaction fails ❌

🚫 Works mainly with phenols, not simple benzene

🚫 Strongly deactivated rings → Reaction does NOT occur

💡 Special Variation:
👉 Using CCl₄ instead of CHCl₃ → gives –COOH (salicylic acid) instead of –CHO

🎯 Exam Tricks:
✔ Always check free ortho/para position
✔ Identify reagent: CHCl₃/NaOH → think “–CHO”
✔ CCl₄/NaOH → think “–COOH”


📌 Save this for revision 🔁

🔥 REIMER–TIEMANN REACTION – PYQs + TRICKY MCQs 🔥

🧪 Q1 (PYQ Level):
Phenol + CHCl₃ + NaOH gives major product?
A) Benzaldehyde
B) o-Hydroxybenzaldehyde
C) p-Hydroxybenzaldehyde
D) Benzoic acid

👉 Answer: B

🧪 Q2 (Concept Check):
The electrophile involved in Reimer–Tiemann reaction is:
A) :CHCl₃
B) :CCl₂
C) CHO⁺
D) Cl⁺

👉 Answer: B

🧪 Q3 (Tricky):
If para position of phenol is blocked, product formed will be:
A) Only para product
B) Only ortho product
C) Both ortho & para
D) No reaction

👉 Answer: B

🧪 Q4 (PYQ Type):
Phenol reacts with CCl₄/NaOH, product is:
A) Salicylaldehyde
B) Salicylic acid
C) Benzaldehyde
D) Phenyl chloride

👉 Answer: B

🧪 Q5 (Exception Based):
If both ortho positions are blocked, Reimer–Tiemann reaction:
A) Gives para product
B) Gives ortho product
C) Does not occur
D) Gives benzoic acid

👉 Answer: C

🧪 Q6 (Mechanism Trap):
Intermediate formed from CHCl₃ in base is:
A) Carbocation
B) Carbanion
C) Carbene
D) Free radical

👉 Answer: C

🧪 Q7 (High Level Trick):
Major product of Reimer–Tiemann reaction is ortho due to:
A) Steric hindrance
B) Intramolecular H-bonding
C) Resonance only
D) Inductive effect

👉 Answer: B

🧪 Q8 (Advanced):
Which compound will NOT undergo Reimer–Tiemann reaction?
A) Phenol
B) Anisole
C) Nitrobenzene
D) Cresol

👉 Answer: C

🧪 Q9 (Mixed Concept):
Which reagent generates dichlorocarbene?
A) CHCl₃ + NaOH
B) CCl₄ + NaOH
C) CH₃Cl + NaOH
D) CH₂Cl₂ + NaOH

👉 Answer: A

🧪 Q10 (JEE Advanced Level):
Major product of Reimer–Tiemann reaction is stabilized by:
A) Intermolecular H-bonding
B) Intramolecular H-bonding
C) π-π stacking
D) Ionic bonding

👉 Answer: B

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3 months ago | [YT] | 9

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3 months ago | [YT] | 5

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youtube.com/shorts/l4MoC1HaTJ...
If you are worried about your exam then listen it.

3 months ago | [YT] | 7

CHEMOXY CLASSES

youtube.com/playlist?list=PLT...

Complete Isomerism for NEET | IIT-JEE | Olympiad is uploaded
Join the membership to get access to all lectures.
Soon other courses will also be uploaded on community itself

Thankyou

3 months ago | [YT] | 4

CHEMOXY CLASSES

May this Holi fill your life with bright colors of joy and hope.
Let the splashes of happiness wash away all worries and stress.
May love, laughter, and togetherness color every moment of your life.💖🥰🙏🏻😇😊
Wishing you sweet memories, warm smiles, and vibrant new beginnings.
Happy Holi to you and your family!

Regards
Agrim Singhal 🙏🏻☺️

3 months ago | [YT] | 11

CHEMOXY CLASSES

youtube.com/shorts/G6h4raoQ-c...

Free radical is what?- Many toppers give wrong answer😲😲😲

4 months ago | [YT] | 9