Let $A=\left\{1,2,\left\{3,4\right\},5\right\}$. Which of the following statements are incorrect and why?
(i) $\left\{3,4\right\}\subset A$ 

(ii) $\left\{3,4\right\}ϵA$ 

(iii) $\left\{\left\{3,4\right\}\right\}\subset A$
(iv) $1ϵA$ 

(v) $1\subset A$ 

(vi) $\left\{1,2,5\right\}\subset A$
(vii) $\left\{1,2,5\right\}ϵA$ 

(viii) $\left\{1,2,3\right\}\subset A$ 

(ix) $\varphi ϵA$
(x) $\varphi \subset A$ (xi) $\left\{\varphi \right\}\subset A$

Given $A=\left\{1,2,\left\{3,4\right\},5\right\}$

(i) The statement $\{3,4\}\subset A$ is incorrect because $3\in \{3,4\}$; however, $3\notin A$.

(ii) The statement $\{3,4\}\in A$ is correct because $\{3,4\}$ is an element of A.

(iii) The statement $\{\{3,4\}\}\subset A$ is correct because $\{3,4\}\in \{\{3,4\}\}$ and $\{3,4\}\in A$.

(iv) The statement $1\in A$ is correct because 1 is an element of A.

(v) The statement $1\subset A$ is incorrect because an element of a set can never be a subset of itself.

(vi) The statement $\{1,2,5\}\subset$ A is correct because each element of $\{1,2,5\}$ is also an element of A.

(vii) The statement $\{1,2,5\}\in A$ is incorrect because $\{1,2,5\}$ is not an element of A.

(viii) The statement $\{1,2,3\}\subset A$ is incorrect because $3\in \{1,2,3\}$; however, $3\notin A$.

(ix) The statement $\varphi \in A$ is incorrect because $\varphi$ is not an element of A.

(x) The statement $\varphi \subset A$ is correct because $\varphi$ is a subset of every set.

(xi) The statement $\left\{\varphi \right\}\subset A$ is incorrect because $\varphi ϵ\left\{\varphi \right\}$; however, $\varphi \notin A$.