Председатель отчитался о ремонте.

Because председатель is the subject of the sentence — the person who performed the action.

• председатель = the chairperson / chairman / chair
• In dictionary form, masculine nouns like this are usually shown in the nominative singular.
• The sentence is about what the chairperson did, so nominative is the expected case.

So:

• Председатель = the chairperson did something.

Отчитался is the past tense, masculine singular form of отчитаться.

In this context, отчитаться means:

• to report
• to give an account
• to report back
• sometimes to account for what was done

So Председатель отчитался о ремонте means that the chairperson gave a report about the repairs or reported on the repairs.

This verb often suggests that someone was expected to give a report, update, or formal account.

The verb is отчитаться, not отчитать or отчитать кого-то.

The ending -ся is part of the verb itself. It does not literally mean himself here. In Russian, many verbs with -ся develop their own meanings, and you often need to learn them as separate vocabulary items.

Compare:

• отчитывать / отчитать кого-то = to scold someone
• отчитываться / отчитаться = to report, to give an account

So in this sentence, -ся is not optional.
You need отчитался, because that is the correct verb for reported.

Because the verb отчитаться commonly takes the preposition о / об when you say what the report was about.

• отчитаться о чём? = to report about what?
• о ремонте = about the repairs / about the renovation

After о / об, Russian normally uses the prepositional case.

So:

• nominative: ремонт
• prepositional: о ремонте

That is why the sentence says о ремонте.

Ремонте is the prepositional singular form of ремонт.

The noun is:

• dictionary form: ремонт
• after о: о ремонте

For many masculine nouns ending in a consonant, the prepositional singular ends in -е:

• проект → о проекте
• договор → о договоре
• ремонт → о ремонте

So the pattern is very regular here.

It tells us three things:

1. Past tense
   The action happened in the past.

2. Masculine singular subject
   The ending -лся in отчитался agrees with a masculine singular subject:

   • он отчитался
   • председатель отчитался

3. Completed action
   This is the perfective verb отчитаться, so it presents the reporting as a completed event.

Compare:

• отчитывался = was reporting / used to report / reported (imperfective, focusing on process or repeated action)
• отчитался = reported, finished giving the report (perfective)

Russian uses the perfective when the speaker sees the action as a whole, completed event.

So отчитался suggests:

• the chairperson gave the report,
• the reporting is treated as finished,
• the result matters more than the process.

If you used отчитывался, the meaning would shift toward:

• the process of reporting,
• repeated reporting,
• background information,
• or an unfinished/imprecisely framed action.

So in a simple statement like this, отчитался naturally means reported / gave his report as a completed act.

Yes. Ремонт is broader than English repair in many contexts.

Depending on the situation, it can mean:

• repair work
• renovation
• maintenance work
• redecoration in some everyday situations

So о ремонте could be understood as:

• about the repairs
• about the renovation
• about the repair work

The best English translation depends on context.

Yes. Russian word order is flexible, although the neutral order here is very natural:

• Председатель отчитался о ремонте.

You could also say:

• О ремонте председатель отчитался.
• Отчитался председатель о ремонте.

These alternatives may change the emphasis:

• О ремонте... puts focus on the repairs
• Отчитался председатель... can emphasize the fact that it was the chairperson who reported

But without a special reason, the original order is the most neutral and natural.

Grammatically, председатель is a masculine noun, so in this sentence the verb is masculine too: отчитался.

However, the word can refer to either a man or a woman depending on context. In modern usage, if the chairperson is a woman, Russian often still uses председатель, but agreement may vary depending on style and register.

For a male chairperson:

• Председатель отчитался.

For a female chairperson, you may encounter:

• Председатель отчиталась.

So the noun is grammatically masculine, but real-life reference can be male or female.

A natural question would be:

• О чём отчитался председатель? = What did the chairperson report on?

This shows the government pattern clearly:

• отчитаться о чём? = to report on what?

You could also ask:

• Кто отчитался о ремонте? = Who reported on the repairs?
• Председатель отчитался о ремонте? = Did the chairperson report on the repairs?

These are useful models for reusing the sentence structure.