На кухне стоит старая табуретка, на которую кошка иногда прыгает.

In Russian, на кухне is the normal idiomatic way to say in the kitchen. Even though на often means on, with some places Russian uses на where English uses in.

Here кухне is in the prepositional case, because на + prepositional is used for location:

• кухня → на кухне

So На кухне means in the kitchen.

The base form is кухня. After на when you are talking about being in a place, Russian usually uses the prepositional singular.

For many feminine nouns ending in -я, that gives:

• кухня → кухне

So:

• на кухне = in the kitchen

Russian often uses different verbs for where things are, depending on their physical position:

• стоять = to stand
• лежать = to lie
• висеть = to hang

A stool is thought of as something that stands upright on its legs, so стоит is the natural choice. The sentence is literally something like In the kitchen stands an old stool.

Russian usually does not use есть in this kind of sentence. Instead of saying There is an old stool in the kitchen, Russian normally just says На кухне стоит старая табуретка.

Using есть here would sound unnatural or at least unnecessary. The idea of existence is already clear from the sentence structure.

Because старая has to agree with табуретка in gender, number, and case.

Here:

• табуретка is feminine
• singular
• nominative, because it is the subject of стоит

So the adjective also takes the feminine singular nominative form:

• старый → старая

Табуретка means a stool, usually a small seat without a back. It is not the same as стул, which is a chair.

So this sentence specifically refers to a stool, not just any seat.

Because на которую кошка иногда прыгает is a relative clause: it describes табуретка.

Russian normally separates this kind of descriptive subordinate clause with a comma:

• старая табуретка, на которую...

It works like English the old stool, which the cat sometimes jumps onto.

The word которую refers back to табуретка, so it must match it in:

• gender: feminine
• number: singular

But its case depends on its role inside the relative clause, not in the main clause. In кошка иногда прыгает на которую, the pronoun is the object of на with a motion verb, so it must be accusative.

That gives:

• которая = nominative
• которую = accusative feminine singular

So которую is correct here.

Because the verb phrase is прыгать на что? = to jump onto what? The preposition belongs to the verb pattern, so it stays with the relative pronoun.

Compare:

• кошка прыгает на табуретку
• табуретка, на которую кошка прыгает

English sometimes leaves the preposition to the end, but Russian usually keeps it directly before the relative pronoun.

Прыгает is imperfective, and that fits well with иногда because the sentence describes a repeated/habitual action: the cat sometimes jumps onto it.

• прыгнет would suggest a single future action
• запрыгивает is also possible in some contexts, but it adds more of the sense of jumping up onto something

Here прыгает is the simplest and most neutral choice.

Russian word order is flexible, and adverbs like иногда can move around. In this sentence, кошка иногда прыгает sounds natural and neutral.

You could also say:

• на которую иногда прыгает кошка
• на которую кошка прыгает иногда

But the emphasis changes a little. The given order is a very normal one.

Russian often puts the setting or location first. Starting with На кухне sets the scene before introducing the object.

So the sentence flows like:

• In the kitchen, there stands an old stool...

You could also say:

• Старая табуретка стоит на кухне...

That is also grammatical, but it gives a slightly different information focus.