يذوب الطعام في المجمد.

Because this is a normal verbal sentence in Modern Standard Arabic. A very common word order is:

verb + subject + other information

So:

يذوب الطعام في المجمد

literally follows the pattern melts + the food + in the freezer.

You can also say:

الطعام يذوب في المجمد

but that makes الطعام more of the topic, similar to The food melts in the freezer with extra focus on the food.

يذوب is in the imperfect form. In Arabic, the imperfect can express:

• the present: melts / is melting
• a habitual action: melts
• sometimes the future, depending on context

So by itself, يذوب does not mean only one English tense. Context tells you whether it is melts, is melting, or something similar.

A likely fully vowelled version is:

يَذُوبُ الطَّعَامُ فِي المُجَمِّدِ

This shows:

• يَذُوبُ = nominative/imperfect ending -u
• الطَّعَامُ = the subject, also nominative
• فِي = the preposition in
• المُجَمِّدِ = genitive after في

In normal everyday writing, these short vowels are usually omitted.

Because ط is a sun letter. When الـ comes before a sun letter, the l sound is not pronounced, and the next consonant is doubled.

So:

• written: الطعام
• pronounced: aṭ-ṭaʿām

This is a very common rule in Arabic pronunciation.

You usually need context, prior knowledge, or a dictionary.

In this sentence, if the intended meaning is the freezer, the word is commonly read as:

المُجَمِّد

That is why unvowelled Arabic can be tricky for learners: the spelling often does not show the short vowels that tell you the exact form.

في is the preposition in.

It introduces a prepositional phrase:

في المجمد = in the freezer

It also causes the following noun to be in the genitive case, which is why the fully vowelled form is:

فِي المُجَمِّدِ

with -i at the end.

In the fully vowelled sentence:

يَذُوبُ الطَّعَامُ فِي المُجَمِّدِ

• الطَّعَامُ takes nominative case because it is the subject of the verb
• المُجَمِّدِ takes genitive case because it comes after the preposition في

So the endings are:

• الطعامُ
• المجمدِ

In normal writing, these endings are usually not shown.

Here it is intransitive. That means the subject itself undergoes the action:

يذوب الطعام = the food melts

There is no direct object.

If you wanted to say something melts the food, Arabic would normally use a different verb form, such as:

يُذيب = melts something / causes something to melt

So the difference is roughly:

• يذوب = to melt
• يذيب = to melt something

Grammatically, yes. But semantically it may sound a bit unusual, because food normally freezes in a freezer rather than melts.

So if the intended real-world meaning is about what happens in a freezer, a more natural sentence might be:

يتجمّد الطعام في المجمد = The food freezes in the freezer

or

يُحفَظ الطعام في المجمد = The food is kept in the freezer

So a learner might understand the grammar perfectly and still feel that the sentence itself is a little odd in meaning.