Identify the ions present in solid M based on the provided qualitative analysis test results.

Here are the observations and inferences for the tests on solid M:

c) To second portion deep a glass rod and heat the glass rod on a non-luminous flame.

Observations	Inferences
No characteristic flame color.	$\boxed{\text{Absence of } \text{Na}^{+}, \text{K}^{+}, \text{Ca}^{2+}, \text{Ba}^{2+}, \text{Cu}^{2+} \text{ ions.}}$

d) To the third portion, add a few drop of lead (II) nitrate and warm slightly.

Observations	Inferences
A white precipitate forms.	$\boxed{\text{Sulfate ions } (\text{SO}_{4}^{2-}) \text{ are present.}}$

e) To the forth portion add 2 drops of barium nitrate solution followed by $\text{1 cm}^{3}$ of dilute nitric acid.

Observations	Inferences
A white precipitate forms.	$\boxed{\text{Sulfate ions } (\text{SO}_{4}^{2-}) \text{ are present.}}$

f) To the fifth portion add 2 drops of acidified potassium manganate (vii).

Observations	Inferences
The purple solution remains purple.	$\boxed{\text{Absence of reducing agents (e.g., } \text{SO}_{3}^{2-}, \text{NO}_{2}^{-}, \text{Fe}^{2+}).}$