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Every time you execute a go statement it is passed to the scheduler. What if scheduling is delayed? wg.Add(1) is not executed and wg.Wait() is true. For example, run your code in the Go Playground.

package main

import (
    "sync"
)

func main() {
    n := 5
    var wg sync.WaitGroup
    wg.Add(n)
    ch := make(chan int, n)
    for i := 0; i < n; i++ {
        println("Processing ", i)
        go process(i, ch)
        go consume(ch, &wg)
    }
    wg.Wait()
    println("Finished the process")
}

func consume(ch chan int, wg *sync.WaitGroup) {
    defer wg.Done()
    println("Result ", <-ch)
}

func process(i int, ch chan int) {
    ch <- (i * 5)
}

Playground: https://play.golang.org/p/dQ_lFRz2Y8a

Output:

Processing  0
Processing  1
Processing  2
Processing  3
Processing  4
Finished the process

Make sure that all the wg.Adds are run before wg.Wait. Move the println("Finished the process") to nthe correct place. For example,

package main

import (
    "sync"
)

func main() {
    n := 5
    var wg sync.WaitGroup
    wg.Add(n)
    ch := make(chan int, n)
    for i := 0; i < n; i++ {
        println("Processing ", i)
        go process(i, ch)
        go consume(ch, &wg)
    }
    wg.Wait()
    println("Finished the process")
}

func consume(ch chan int, wg *sync.WaitGroup) {
    defer wg.Done()
    println("Result ", <-ch)
}

func process(i int, ch chan int) {
    ch <- (i * 5)
}

Playground: https://play.golang.org/p/rBp62M4_PwU

Output:

Processing  0
Processing  1
Processing  2
Processing  3
Processing  4
Result  0
Result  5
Result  10
Result  15
Result  20
Finished the process