Если оставить бельё на балконе во время дождя, оно намокнет.

Russian often uses an infinitive after если when the subject is general or unspecified, like if one leaves... or if you leave... in a general sense.

So:

Если оставить бельё на балконе...
= If you leave / if one leaves the laundry on the balcony...

If you want to name the subject explicitly, you can do that too:

Если вы оставите бельё на балконе...

Both are natural. The infinitive version sounds more general and impersonal.

This is about aspect.

• оставить = perfective
• оставлять = imperfective

Here the sentence means a single completed action: first the laundry is left on the balcony, then as a result it gets wet. That is why оставить is used.

Compare:

• Если оставить бельё на балконе, оно намокнет.
  = If you leave it there, it will get wet.
  One specific action leads to one result.

• Если оставлять бельё на балконе во время дождя, оно намокает.
  = If you leave laundry on the balcony during rain, it gets wet.
  This sounds habitual or repeated.

So the given sentence uses the perfective because it describes a single condition with a future result.

In Russian, бельё is a singular neuter noun, even though in English laundry may feel like a collection of things.

That is why the pronoun is:

• оно = it

not:

• они = they

This is very normal in Russian. Бельё is a collective or mass noun, grammatically singular.

Бельё can mean different things depending on context:

• laundry
• linen
• underwear

In this sentence, because it is being left on the balcony and can get wet in the rain, the natural meaning is laundry or washing.

So context matters a lot with this word.

Because this sentence describes location, not movement.

• на балконе = on the balcony / on the balcony area
  This is the prepositional case, used with на for location.

• на балкон = onto the balcony
  This is the accusative case, used with на for direction or movement.

Compare:

• оставить бельё на балконе = leave the laundry on the balcony
• вынести бельё на балкон = take the laundry out onto the balcony

The phrase во время is a fixed expression meaning during.

There are two things to notice:

1. во instead of в
   Russian often uses во instead of в when it is easier to pronounce.
   Since время begins with a difficult consonant cluster after в, Russian says во время.

2. дождя is in the genitive case
   The expression во время requires the genitive:

   • во время урока
   • во время дождя
   • во время поездки

So во время дождя literally means during the rain.

Because во время governs the genitive.

The base noun is:

• дождь = rain

Its genitive singular form is:

• дождя

So:

• во время дождя = during the rain

This is something you usually just learn as part of the whole expression во время + genitive.

Намокнет means will get wet.

It comes from the verb:

• намокнуть = to become wet

This is slightly different from simply describing a state. For example:

• оно мокрое = it is wet
• оно намокнет = it will become wet / get wet

So намокнет focuses on the change of state.

Намокнет is the future form of the perfective verb намокнуть.

In Russian:

• imperfective future is usually formed with быть

  • infinitive
    for example: будет мокнуть or more naturally with another verb

• perfective verbs form the future with simple endings
  for example:
  намокну, намокнешь, намокнет...

So намокнет is not present tense here. With a perfective verb, that form means future:

• оно намокнет = it will get wet

Sometimes yes, but the meaning shifts a bit.

• намокнуть = to get wet
• промокнуть = to get soaked through, to become thoroughly wet

For laundry in the rain, намокнет is a very natural and neutral choice.
Промокнет would suggest stronger soaking.

So the original sentence sounds completely normal.

Yes. In Russian, a subordinate clause introduced by если is separated by a comma from the main clause.

So:

Если оставить бельё на балконе во время дождя, оно намокнет.

The comma marks the boundary between:

• the condition: Если оставить бельё на балконе во время дождя
• the result: оно намокнет

Yes. Russian word order is flexible.

You can also say:

Оно намокнет, если оставить бельё на балконе во время дождя.

That means the same thing. The difference is mostly in emphasis:

• Если ... , оно намокнет puts the condition first
• Оно намокнет, если ... puts the result first

Both are correct.

Sometimes Russian can omit subjects, but here оно is natural and helps clarity.

Because бельё is the subject of the second clause, repeating it with оно makes the sentence clear and complete:

Если оставить бельё на балконе во время дождя, оно намокнет.

Without оно, the sentence is possible in some contexts, but it feels less standard and a little less clear. Keeping оно is the safest and most natural choice for learners.

Yes, both for pronunciation and sometimes for clarity.

• бельё is pronounced with yo: roughly byel-YO
• the stress is on the last syllable

In printed Russian, ё is often written as е, so you may see белье. But it is still understood and pronounced as бельё.

For learners, it is very useful to remember the real pronunciation with ё.