Why not "tocar a arma"? Is "touch (something)" translated as "tocar em (alguma coisa)"?
Most of time! Dont touch me = não toque em mim, but "dont touch here" = não toque aqui
This is where little explanation notes would be useful, especially when you get it wrong. A learner wouldn't know tocar is usually followed by em.
"Tocar a" is formal and "tocar na" is informal when we use the word "tocar" as the word "touch".
So is "na" used here because it's like saying "she touches her finger on the gun"?
When do you use "na" with tocar? When there is an object directly named?
Well, like @Paulenrique explained above, "tocar" is usually followed by "em", so it's basically "tocar em a arma", where "em" and "a" are contracted to "na".
Someone already explained it above... Anyway, certain verbs have prepositions that go with them, and this either may alter or completely change the verbs meaning, or just be grammatically required; I think these verbs are called "prepositional verbs," but I'm not sure. Anyway, Tocar can mean to play an instrument and to ring. (that is tocar without a preposition) The so-called prepositional verb "variation" is "Tocar + Em" and that means to touch. So, everytime you want to say to touch, you have to use tocar+ em. And since em is contracted with definite articles like "o" "a," you have to say either "tocar no/na/nos/nas."
Arma is gun or weapon (a noun) not a body part. The hints may have confused you because the verb form translates to 'arms' in English - as in: she arms herself with a pistol.
Sorry Gregor, but "ring" isn,t the same. Ring reffers to the sound of the phone, cell phone, bell, door bell etc.
I can "tocar" a musical instrument too, but in this case, "tocar" means "play". For example" She plays the violin = ela toca violino.
The "ing" suffix in the verb touch is not acceptable? E. g. "She tries touching on the gun"?
You can use the -ing form, but not the preposition "on".
"She tries touching the gun" works, but sounds a bit odd.