Se esco adesso, arrivo in tempo.

Because uscire is an irregular verb in the present tense. The io form is esco.

Present tense of uscire:

• io esco
• tu esci
• lui/lei esce
• noi usciamo
• voi uscite
• loro escono

So Se esco adesso... is the correct form for if I go out now / if I leave now.

Italian often leaves out subject pronouns when they are not needed. The verb ending already tells you who the subject is.

Here:

• esco = I go out / I leave
• arrivo = I arrive

So io is understood automatically. You could say Se io esco adesso, arrivo in tempo, but that sounds more emphatic, as if you are stressing I specifically.

This is very normal in Italian. In a real or likely condition, Italian often uses the present tense in both parts:

• Se esco adesso, arrivo in tempo.

Even though English may say If I leave now, I’ll arrive on time, Italian very naturally uses the present: esco + arrivo.

This is sometimes called a real condition:

• se
  • present
• present in the main clause

You could also sometimes hear the future in the second part, but the present is extremely common here.

Yes. That is also correct.

Difference in feel:

• Se esco adesso, arrivo in tempo = very natural, direct, conversational
• Se esco adesso, arriverò in tempo = also correct, a bit more explicitly future-oriented

Italian uses the present tense more broadly than English does, especially for near-future situations.

Yes, you could use ora instead. Both adesso and ora can mean now.

So these are both natural:

• Se esco adesso, arrivo in tempo.
• Se esco ora, arrivo in tempo.

In many situations, the difference is very small. Adesso can sometimes feel a little more emphatic, but in everyday speech they are often interchangeable.

In tempo is a fixed expression meaning on time or in time, depending on context.

So:

• arrivare in tempo = to arrive on time / in time

You do not normally say nel tempo for this meaning.

A few useful related expressions:

• essere in tempo = to be in time
• arrivare in tempo = to arrive in time
• arrivare in ritardo = to arrive late

The comma is standard and very common when the se clause comes first:

• Se esco adesso, arrivo in tempo.

It helps separate the condition from the result. In very informal writing, some people may omit it, but using the comma is a good habit.

If you reverse the order, the comma is often not used:

• Arrivo in tempo se esco adesso.

Yes. You can say:

• Se esco adesso, arrivo in tempo.
• Arrivo in tempo se esco adesso.

Both are correct.

The version with se first is often a little more neutral or natural when introducing the condition first. The reversed order can sound slightly more focused on the result: I’ll make it on time, if I leave now.

A simple pronunciation guide:

• Se ≈ seh
• esco ≈ ES-ko
• adesso ≈ ah-DESS-so
• arrivo ≈ ar-REE-vo
• in tempo ≈ een TEM-po

The stress falls on:

• ESco
• aDESso
• arRIvo
• TEMpo

Also note:

• the sc in esco is a hard sk sound, because it comes before o
• rr in arrivo is rolled or tapped in Italian

Either can work, depending on context.

The verb uscire basically means to go out, to go बाहर, or to leave in the sense of going out from a place.

So:

• Se esco adesso... can mean If I go out now...
• in this sentence, natural English often becomes If I leave now...

That does not change the Italian grammar. It is just a matter of choosing the most natural English translation for the situation.

This is the basic, real-life type of conditional: a condition that is possible and realistic.

Pattern:

• Se
  • present tense
• present tense or future in the main clause

Examples:

• Se studio, passo l’esame.
• Se parto adesso, arrivo presto.
• Se esco adesso, arrivo in tempo.

This is different from hypothetical or unreal conditionals, which use different tenses, such as:

• Se uscissi adesso, arriverei in tempo.

That would mean something more like If I left now, I would arrive on time.