Не торкайся гарячої плити, будь ласка.

Because торка́тися/торкну́тися governs the genitive. Think of it as “to touch (of) something.”

• Не торкайся гарячої плити.
• Other examples: не торкайся води, не торкайся вогню, не торкайся цієї кнопки.

If you switch to the verb чіпа́ти (“to touch, to handle”), you use the accusative: не чіпай гарячу плиту.

Yes. Не чіпай гарячу плиту is very common and idiomatic. Nuance:

• торка́тися/торкну́тися = “touch (make contact with),” often a brief contact; genitive.
• чіпа́ти = “touch/handle/fiddle with,” often implies more active handling; accusative.

Both work as a warning; choose either based on the nuance you want.

Aspect:

• Не торкайся (imperfective) bans the action in general/ongoing terms: “Don’t be touching / Don’t touch (at all).”
• Не торкнися/Не торкнись (perfective) bans a single act: “Don’t touch (even once).” It can sound sharper/more urgent.

Both are correct; for a general safety rule, imperfective is a safe default.

Better options:

• Standard with no preposition: Не торкайся гарячої плити.
• Or use the prefixed verb with до: Не доторкайся до гарячої плити.

You will hear торкатися до in speech, but the most standard patterns are торкатися + genitive and доторкатися до + genitive.

Case agreement. Feminine adjective гарячий/гаряча changes with the noun’s case:

• Nominative: гаряча плита (“a hot stove”)
• Accusative: гарячу плиту (with чіпати)
• Genitive: гарячої плити (with торкатися)

Stresses (marked with an acute): Не торка́йся гаря́чої плити́, будь ла́ска. Quick tips:

• г is a voiced “h,” not a hard “g.”
• и is like short “i” [ɪ], as in “bit.”
• й gives a “y” glide; ї is “yi.”
• Final -и in плити́ is stressed. A simple stress guide: ne tor-KAI-sia ha-RYA-cho-yi pli-TY, bud’ LAS-ka.

Будь ласка is a parenthetical politeness marker and is set off by a comma.

• End: Не торкайся гарячої плити, будь ласка.
• Beginning: Будь ласка, не торкайся гарячої плити. Both are fine. An exclamation mark is also possible for urgency.

Literally “be kind.” It’s the standard, neutral “please.” Alternatives:

• Прошу can mean “please,” but also “you’re welcome / here you go / come in,” depending on context and region—use with care.
• Будь ласкавий/ласкава
  • verb is a more personal/old-fashioned “be so kind (as to)...”

Mostly yes in kitchen contexts. But it can also mean “slab/plate” (e.g., concrete slab). Related words:

• плитка = “tile” or a small hotplate; also “a bar” (of chocolate).
• варильна поверхня = “hob/cooktop,” духовка = “oven,” піч = “(wood-burning) stove.”