ज़हर बच्चे से दूर रखिए।

Because से is a postposition, and nouns usually switch to the oblique form before a postposition.

• basic form: बच्चा = child
• oblique singular: बच्चे
• so: बच्चे से = from the child

This is very common in Hindi:

• लड़का → लड़के से
• कमरा → कमरे में
• बच्चा → बच्चे से

So बच्चे here is not the plain plural children. It is the singular oblique form of बच्चा.

Here से means from.

In this sentence, it marks separation or distance:

• बच्चे से दूर = away from the child

This use is very common with words like दूर:

• घर से दूर = far from home
• आग से दूर = away from fire
• बच्चे से दूर = away from the child

So से is not doing something complicated here; it is simply showing what something should be kept away from.

Grammatically, बच्चे से normally means from the child or from a child, because it is singular oblique.

If you wanted from children, you would usually say:

• बच्चों से

Compare:

• बच्चे से = from the child
• बच्चों से = from children

This is important because English warning labels often say Keep out of reach of children, and in Hindi a more typical general warning would use बच्चों rather than बच्चे.

रखिए is a polite imperative form of रखना, which means to keep / to place.

So रखिए means something like:

• keep
• please keep

It is respectful and appropriate for instructions, warnings, notices, and formal speech.

Some related forms are:

• रख = very informal command
• रखो = familiar command
• रखिए = polite command
• रखिये = same pronunciation, alternate spelling you may also see

So this sentence is phrased as a polite instruction, not a harsh command.

Because को is often omitted with inanimate direct objects, especially when they are general rather than strongly specific.

So both of these are possible:

• ज़हर बच्चे से दूर रखिए।
• ज़हर को बच्चे से दूर रखिए।

The version without को is perfectly normal.

A rough rule:

• with people/animate specific objects, को is much more common
• with inanimate things, को is often optional

Since ज़हर is an inanimate noun, leaving out को sounds natural.

दूर means far or away.

In this sentence, it works with रखिए to give the idea keep away.

So the structure is basically:

• X Y से दूर रखिए = keep X away from Y

Examples:

• आग बच्चों से दूर रखिए। = Keep fire away from children.
• दवा धूप से दूर रखिए। = Keep the medicine away from sunlight.

You can think of दूर रखना as a very common Hindi combination meaning to keep away.

Hindi word order is flexible, though some orders sound more natural in context.

The given order:

• ज़हर बच्चे से दूर रखिए।

is natural and clear.

You could also hear:

• बच्चे से ज़हर दूर रखिए।
• ज़हर को बच्चे से दूर रखिए।

All of these are understandable. Hindi often places the main object before the verb, and the verb usually comes at the end.

So the most important thing is not memorizing one rigid order, but noticing that:

• रखिए usually comes last
• बच्चे से दूर stays together as a phrase
• ज़हर is the thing being kept away

It is understandable, but for a general safety warning, Hindi more often says something like:

• ज़हर बच्चों से दूर रखें।
• बच्चों की पहुँच से दूर रखें।

Why?

Because warning labels usually mean children in general, not one child. So बच्चों is more typical than बच्चे in that context.

A very common packaging-style phrase is:

• बच्चों की पहुँच से दूर रखें = Keep out of reach of children

So the given sentence is grammatically fine, but in real-life warning language, you will often see a slightly different version.

Yes: ज़हर is a masculine noun meaning poison, and it does not change form here.

Unlike बच्चा, which changes to बच्चे before a postposition, ज़हर stays the same in this sentence because it is not followed by a postposition and is being used as the direct object.

Also, many Hindi nouns do not show an obvious visible change the way -ा nouns do. So learners often notice बच्चा → बच्चे, but ज़हर remains ज़हर.

Yes, that is a very helpful way to understand the grammar.

A literal breakdown is:

• ज़हर = poison
• बच्चे से = from the child
• दूर = away / far
• रखिए = keep

So the structure is basically:

Poison, from the child away keep.

That is not natural English word order, but it mirrors the Hindi grammar well and can help you remember how the sentence is built.