Naming Organic Compounds Practice - Fill and Sign Printable ... - Free Printable

Let’s go through each compound one by one. We’ll identify the class (like alkane, alkene, alcohol, etc.) and then give the IUPAC name — or common name if it’s benzene or a substituted benzene.

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1)
Structure: A six-membered ring with alternating double bonds → that’s benzene.
Class: Aromatic hydrocarbon (specifically, benzene)
Name: Benzene (common name is used as instructed)

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2)
Structure: CH₃–CH(CH₃)–CH₂–CH₃
That’s a 4-carbon chain with a methyl group on carbon #2.
Longest chain: 4 carbons → butane
Branch: methyl on carbon 2
Class: Alkane
Name: 2-Methylbutane

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3)
Structure: HO–CH₂–CH₂–CH₂–OH
Two OH groups at ends of a 3-carbon chain.
Class: Diol (alcohol with two OH groups)
IUPAC: Propane-1,3-diol
(We number from end to give lowest numbers to OH groups → both are on 1 and 3)
Name: Propane-1,3-diol

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4)
Structure: CH₃–C(OH)(CH₃)–CH₂–CH₂–CH₂–CH₃
OH group attached to a carbon that also has two methyl groups? Wait — let’s redraw:

Carbon 1: CH₃–
Carbon 2: C with OH and another CH₃ → so it’s tertiary carbon
Then –CH₂–CH₂–CH₂–CH₃

So longest chain: from left CH₃ through C(OH)(CH₃) to the end → that’s 6 carbons? Let’s count:

Start from right: CH₃–CH₂–CH₂–CH₂–C(OH)(CH₃)–CH₃ → that’s 6 carbons total. The OH is on carbon 2 (if we number from right), or carbon 5 (from left). Better to number so OH gets lower number.

Number from left:
C1: CH₃–
C2: C(OH)(CH₃)– → this carbon has OH and a methyl branch
C3: CH₂
C4: CH₂
C5: CH₂
C6: CH₃

Wait — actually, the structure is written as:

CH₃
|
HO–C–CH₂–CH₂–CH₂–CH₃
|
CH₃

So the central carbon has: OH, CH₃, CH₃ (another methyl?), no — wait, looking again:

It says:
CH₃
|
HO–C–CH₂–CH₂–CH₂–CH₃
|
CH₃

Actually, that’s not possible — carbon can’t have 5 bonds. Probably typo in drawing? Let me re-read:

Original:
“4) H₃C–C–CH₂–CH₂–CH₂–CH₃
|
OH
|
CH₃”

Ah — so it’s:

CH₃
|
H₃C – C – CH₂ – CH₂ – CH₂ – CH₃
|
OH

So the second carbon has:
- One bond to CH₃ (left)
- One bond to CH₃ (top)
- One bond to OH (bottom)
- One bond to CH₂–CH₂–CH₂–CH₃ (right)

That’s 4 bonds — okay.

So longest chain: from left CH₃ through to end CH₃ → that’s 6 carbons? Left CH₃ is C1, then C2 (the branched one), then C3 to C6.

But C2 has two methyl groups? No — one is part of the main chain? Actually, the main chain should be the longest continuous chain.

If we take the chain as: CH₃–C–CH₂–CH₂–CH₂–CH₃, where the middle C has an extra CH₃ and OH.

So the longest chain is 6 carbons: from the top CH₃? No — better to pick the straightest chain.

Actually, the backbone is: start from the rightmost CH₃, go left: CH₃–CH₂–CH₂–CH₂–C–CH₃, and that C has OH and another CH₃.

So the longest chain is 6 carbons: let’s number from right:

C1: CH₃ (right end)
C2: CH₂
C3: CH₂
C4: CH₂
C5: C (with OH and CH₃)
C6: CH₃ (left)

But C5 has a methyl group and OH → so it’s 2-methylhexan-2-ol? Wait, if we number from left:

C1: CH₃ (left)
C2: C (with OH and CH₃)
C3: CH₂
C4: CH₂
C5: CH₂
C6: CH₃

Same thing. The OH is on C2, and there’s a methyl on C2 → so it’s 2-methylhexan-2-ol? But “2-methyl” and “2-ol” on same carbon — that’s fine.

Actually, the parent chain is hexane, with a methyl substituent on carbon 2, and OH on carbon 2 → so it’s 2-methylhexan-2-ol.

But standard naming: we choose the chain that includes the functional group and is longest. Here, the chain including the OH is 6 carbons, and the branch is a methyl on C2.

Yes.

Class: Alcohol (tertiary alcohol)
Name: 2-Methylhexan-2-ol

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5)
Structure: Benzene ring with a CH₃ group attached → that’s toluene.
Class: Aromatic hydrocarbon
Name: Toluene (common name as instructed)

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6)
Structure: CH₃–CH=C(CH₃)–CH₃
Double bond between C2 and C3? Let’s number:

Left: CH₃–CH=
Then C(CH₃)–CH₃ → so the third carbon has a methyl group.

So:
C1: CH₃–
C2: CH=
C3: C(CH₃)–
C4: CH₃

But C3 has two groups: the = from C2, and –CH₃, and –CH₃? That would be three bonds? No:

Actually, it’s CH₃–CH=C–CH₃, with a CH₃ attached to the C after the double bond.

So:
Carbon 1: CH₃–
Carbon 2: CH=
Carbon 3: C– (attached to CH₃ and CH₃) → so it’s C with two methyls? Then it’s (CH₃)₂C=

Standard way: CH₃–CH=C(CH₃)₂? But here it’s written as CH₃–CH=C–CH₃ with a CH₃ below the C.

Looking back: “6) H₃C–CH=C–CH₃
|
CH₃”

So the third carbon (after =) has:
- Double bond to C2
- Single bond to CH₃ (right)
- Single bond to CH₃ (below) → so yes, it’s C with two methyl groups.

So the molecule is CH₃–CH=C(CH₃)₂

Longest chain: 4 carbons? C1–C2=C3–C4, but C3 has an extra methyl.

Actually, the chain is: from left CH₃ to the =C, then to one of the methyls — but better to consider the double bond.

Parent chain: 4 carbons with double bond starting at C2.

Substituent: a methyl on C3.

So: but-2-ene with a methyl on C3 → 3-methylbut-2-ene? But let’s number properly.

To give lowest numbers to double bond: number from left:

C1: CH₃–
C2: CH=
C3: C(CH₃)–
C4: CH₃ → but C3 has two carbons attached? In CH₃–CH=C(CH₃)₂, the C after = is attached to two methyl groups, so it’s (CH₃)₂C= part.

Standard name: the longest chain including double bond is 3 carbons? No.

Actually, CH₃–CH=C(CH₃)₂ is 2-methylbut-2-ene? Let’s see:

If we write it as:

CH₃
|
CH₃–CH=C–CH₃ → no, that’s not right.

Better: the carbon of the double bond that has two methyls is C2 if we number from that side.

Set C1 as one of the methyls on the right? Standard way: the base chain is butene: C1–C2=C3–C4.

In this case, it’s CH₃–CH=C–CH₃ with an additional CH₃ on C3 → so C3 has two alkyl groups: methyl and methyl, so it’s 2-methylbut-2-ene? Let’s count atoms.

Total carbons: 5. Chain: if we take C1= the CH₃– (left), C2=CH, C3=C, then C3 is attached to two CH₃ groups → so the longest chain is 3 carbons? No, we can have a chain of 4: for example, CH₃–CH=C–CH₃, and the fourth carbon is the branch.

Actually, the IUPAC name is 2-methylbut-2-ene.

Confirm:
But-2-ene is CH₃–CH=CH–CH₃
Here, instead of H on C3, it’s CH₃, so it’s CH₃–CH=C(CH₃)–CH₃? But that would be C4H8, but with an extra methyl? CH₃–CH=C(CH₃)₂ is C5H10.

Yes: carbon 1: CH₃– (of ethyl part), carbon 2: CH=, carbon 3: C(CH₃)₂ — so the two methyls on C3 are equivalent.

The longest chain is 3 carbons if we go through the double bond, but we include the substituents.

Standard name: the parent chain is butene: we can consider CH₃–CH=C–CH₃ as butene, but with a methyl on C3, so it’s 3-methylbut-2-ene? But numbering: if we number the double bond carbons as 2 and 3, and put the methyl on 3, but to have lowest numbers, we should number so the double bond starts at lowest number.

If we number from the other end: let C1 be one of the methyl groups on the right, C2 be the C with the double bond, C3 be CH, C4 be CH₃ — then double bond is between C2 and C3, and there’s a methyl on C2? So it’s 2-methylbut-2-ene.

Yes:
C1: CH₃– (one of the methyls on the right)
C2: C= (with another CH₃ attached)
C3: CH–
C4: CH₃

So double bond between C2 and C3, methyl group on C2 → so 2-methylbut-2-ene.

Class: Alkene
Name: 2-Methylbut-2-ene

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7)
Structure: CH₃–C(CH₃)=CH–O–CH₃
Wait, it’s written as:
“7) H₃C–C=CH–O–CH₃
|
CH₃”

So:
Carbon 1: CH₃– (left)
Carbon 2: C= (with a CH₃ below)
Carbon 3: CH–
Then –O–CH₃

So it’s an enol ether? Or vinyl ether.

The functional group is ether, but with a double bond.

Class: Ether (specifically, vinyl ether)

For naming: the group attached to oxygen is methoxy, and the other part is 1-methylethenyl or something.

Systematic name: the chain is CH₃–C(CH₃)=CH–O–CH₃

The hydrocarbon part is 2-methylprop-1-en-1-yl? Let’s see.

The carbon attached to O is part of the double bond: it’s =CH–O–, so it’s a vinyl group with a methyl substituent.

The group is (CH₃)₂C=CH–O–CH₃? No, in this case, it’s CH₃–C(CH₃)=CH–O–CH₃, so the double bond is between C2 and C3, with C2 having a methyl group.

So the alkyl group attached to oxygen is 1-methylethenyl? Standard name for (CH₃)₂C=CH– is 2-methylprop-1-en-1-yl, but here it’s CH₃–C(CH₃)=CH–, which is the same as (CH₃)₂C=CH– only if the first CH₃ is part of it.

Actually, CH₃–C(CH₃)=CH– is the same as (CH₃)₂C=CH–, yes, because the carbon has two methyl groups? In the structure, it’s written as H₃C–C=CH– with a CH₃ below the C, so yes, the carbon of the double bond has two methyl groups? No:

H₃C–C=CH–O–CH₃
|
CH₃

So the second carbon (C2) is bonded to:
- C1 (CH₃)
- Another CH₃ (below)
- Double bond to C3 (CH)
So yes, C2 has two methyl groups and is part of the double bond.

So the group is (CH₃)₂C=CH–, which is 2-methylprop-1-en-1-yl? But when attached to oxygen, it’s called 2-methylprop-1-en-1-yloxy or something.

IUPAC name for ethers: we name the two groups attached to oxygen.

One group is methyl (from –O–CH₃)
The other group is (CH₃)₂C=CH–, which is 2-methylprop-1-en-1-yl? But the carbon attached to oxygen is the CH part, which is sp2.

The systematic name is 1-methoxy-2-methylprop-1-ene? Let’s think.

The parent chain could be the alkene: propene with a methoxy on C1 and a methyl on C2.

So: CH₂=C(CH₃)–OCH₃ would be 1-methoxyprop-1-ene, but here it’s (CH₃)₂C=CH–OCH₃, which is the same as CH₂=C(CH₃)–OCH₃? No.

(CH₃)₂C=CH–OCH₃ is different from CH₂=C(CH₃)–OCH₃.

In our case, it’s (CH₃)₂C=CH–OCH₃, so the double bond is between C1 and C2, with C1 being the CH attached to O, C2 being the C with two methyls.

So if we number the alkene chain: C1 is the CH–O, C2 is the C(CH₃)₂, so it’s 2-methylprop-1-ene with methoxy on C1? But C1 is already part of the chain.

Standard way: the compound is named as an alkene with a methoxy substituent.

The longest chain is 3 carbons: C1 (the CH–O), C2 (the C), and then the two methyls are branches.

So: prop-1-ene with a methyl on C2 and a methoxy on C1.

But C1 has the methoxy and is part of the double bond.

So name: 1-methoxy-2-methylprop-1-ene

Yes.

Class: Ether (and alkene) — but primarily classified as ether since the functional group priority might be ether, but in IUPAC, alkenes have higher priority than ethers? No, actually, for naming, we choose the principal functional group.

According to IUPAC priority, alkenes have higher priority than ethers, so it should be named as an alkene with a methoxy substituent.

Yes, so 1-methoxy-2-methylprop-1-ene

But let's confirm the structure: (CH₃)₂C=CH–OCH₃

The carbon of the double bond attached to O is CH, so it's terminal.

Name: the parent is propene: C1=C2–C3, but here C1 is CH–OCH₃, C2 is C(CH₃)₂, so it's 2-methylprop-1-ene with a methoxy on C1 — but C1 is already defined.

In 2-methylprop-1-ene, it's (CH₃)₂C=CH₂, so if we replace one H on CH₂ with OCH₃, it becomes (CH₃)₂C=CH–OCH₃, which is 1-methoxy-2-methylprop-1-ene.

Yes.

Class: Alkene (since double bond has higher priority)
Name: 1-Methoxy-2-methylprop-1-ene

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8)
Structure: H₂C–CH₂
| |
CH₂–CH₂
With OH on one carbon? It’s written as:

“8) H₂C–CH₂
| |
CH₂–CH₂
|
OH”

So it’s a four-membered ring with an OH group → cyclobutanol.

Class: Alcohol (cyclic)
Name: Cyclobutan-1-ol or just Cyclobutanol (since the OH is assumed to be on C1)

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9)
Structure: Not shown? In the original, it might be missing, but looking back, in the user's message, after 8) it goes to 10), so probably 9) is skipped or typo. In the image description, it lists up to 14, but in text, 9) is not there. Perhaps it's a mistake.

In the initial problem statement, it says "for the four special monosubstituted benzenes", but in the list, 1,5,11,12 are benzenes.

For now, skip 9) if not present. But in the user's input, it has:

"8) ...
9) ?
10) ..."

In the text provided, after 8) it says "9)" but no structure, then "10)". Probably a formatting error. Looking at the original image description, it might be that 9) is not included, or perhaps it's implied.

To be safe, I'll assume 9) is missing and move to 10).

But in the user's message, it has:

"8) H₂C–CH₂
| |
CH₂–CH₂
|
OH
9)
10) H₃C–CH₂–CH₂–CH₂–CH₂–CH₂–CH₂–CH₃"

So 9) is blank? Perhaps it's a typo. I'll proceed with 10).

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10)
Structure: CH₃–(CH₂)₆–CH → octane
Class: Alkane
Name: Octane

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11)
Structure: Benzene ring with NO₂ group → nitrobenzene
Class: Aromatic compound (nitro derivative)
Name: Nitrobenzene (common name)

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12)
Structure: Benzene ring with Cl and Br? Written as:

“12) Cl–benzene–Br” but in text: “Cl–C₆H₄–Br” or specifically, it's para or what?

In the image, it's likely 1-bromo-4-chlorobenzene or something.

From the text: “12) Cl–benzene–Br” and it's drawn with Cl and Br opposite, so para.

Class: Aromatic halide
Name: Since it's disubstituted benzene, we use common names or IUPAC.

Common names: for para-disubstituted, we can use p-bromochlorobenzene, but IUPAC prefers numbering.

Since no priority, we alphabetize: bromo before chloro, so 1-bromo-4-chlorobenzene.

But the instruction says "for the four special monosubstituted benzenes, use the common name" — this is disubstituted, so we use IUPAC.

The four special are benzene, toluene, phenol, aniline — this is not one of them.

So name: 1-Bromo-4-chlorobenzene

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13)
Structure: H₃C–CH–CH–CH–CH₃
| | |
CH₃ OH CH₃

So: carbon chain: C1: CH₃–
C2: CH– with CH₃
C3: CH– with OH
C4: CH– with CH₃
C5: CH₃

So longest chain: 5 carbons.

Substituents: methyl on C2, methyl on C4, OH on C3.

Class: Alcohol

Numbering: to give OH the lowest number. If we number from left, OH is on C3; from right, also on C3. So either way.

Alphabetical order for substituents: methyl and methyl, so dimethyl.

Name: 2,4-dimethylpentan-3-ol

Check: pentane chain, OH on 3, methyl on 2 and 4.

Yes.

Name: 2,4-Dimethylpentan-3-ol

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14)
Structure: H₃C–CH–CH₂–CH₂–CH₂–CH₃
|
CH₃

So: CH₃–CH(CH₃)–CH₂–CH₂–CH₂–CH₃

Longest chain: 6 carbons (from left CH₃ through to end CH₃, with a methyl on C2)

Class: Alkane
Name: 2-Methylhexane

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Now, compiling all answers:

1) Benzene
2) 2-Methylbutane
3) Propane-1,3-diol
4) 2-Methylhexan-2-ol
5) Toluene
6) 2-Methylbut-2-ene
7) 1-Methoxy-2-methylprop-1-ene
8) Cyclobutanol
9) [Missing - skip]
10) Octane
11) Nitrobenzene
12) 1-Bromo-4-chlorobenzene
13) 2,4-Dimethylpentan-3-ol
14) 2-Methylhexane

Note: For 9), since it's not provided, we omit it. In some versions, it might be present, but based on given text, we skip.

Also, for 7), some might argue the class is ether, but IUPAC names it as alkene with substituent.

Final Answer:

1) Benzene
2) 2-Methylbutane
3) Propane-1,3-diol
4) 2-Methylhexan-2-ol
5) Toluene
6) 2-Methylbut-2-ene
7) 1-Methoxy-2-methylprop-1-ene
8) Cyclobutanol
10) Octane
11) Nitrobenzene
12) 1-Bromo-4-chlorobenzene
13) 2,4-Dimethylpentan-3-ol
14) 2-Methylhexane

(Note: 9) is omitted as not provided)