diff --git a/src/Methods/EthClient.php b/src/Methods/EthClient.php
index 0368d19..75be518 100644
--- a/src/Methods/EthClient.php
+++ b/src/Methods/EthClient.php
@@ -59,12 +59,12 @@ public function hashRate(): int
         return hexdec($response->getRpcResult());
     }
 
-    public function gasPrice(): Wei
+    public function gasPrice(): ?Wei
     {
         $response = $this->client->send(
             $this->client->request(73, 'eth_gasPrice', [])
         );
-        return new Wei(hexdec($response->getRpcResult()));
+        return ($response->getRpcResult()) ? new Wei(hexdec($response->getRpcResult())) : null;
     }
 
     /**
@@ -90,12 +90,12 @@ public function blockNumber(): int
         return hexdec($response->getRpcResult());
     }
 
-    public function getBalance(Address $address, BlockNumber $blockNumber): Wei
+    public function getBalance(Address $address, BlockNumber $blockNumber): ?Wei
     {
         $response = $this->client->send(
             $this->client->request(1, 'eth_getBalance', [$address->toString(), $blockNumber->toString()])
         );
-        return new Wei(\Phlib\base_convert($response->getRpcResult(), 16, 10));
+        return ($response->getRpcResult()) ? new Wei(\Phlib\base_convert($response->getRpcResult(), 16, 10)) : null;
     }
 
     public function getStorageAt(Address $address, int $quantity, BlockNumber $blockNumber): string
@@ -164,20 +164,20 @@ public function sign(Address $address, string $msgToSign)
         return $response->getRpcResult();
     }
 
-    public function sendTransaction(Transaction $transaction): TransactionHash
+    public function sendTransaction(Transaction $transaction): ?TransactionHash
     {
         $response = $this->client->send(
             $this->client->request(1, 'eth_sendTransaction', [$transaction->toArray()])
         );
-        return new TransactionHash($response->getRpcResult());
+        return ($response->getRpcResult()) ? new TransactionHash($response->getRpcResult()) : null;
     }
 
-    public function sendRawTransaction(string $data): TransactionHash
+    public function sendRawTransaction(string $data): ?TransactionHash
     {
         $response = $this->client->send(
             $this->client->request(1, 'eth_sendRawTransaction', [$data])
         );
-        return new TransactionHash($response->getRpcResult());
+        return ($response->getRpcResult()) ? new TransactionHash($response->getRpcResult()) : null;
     }
 
     public function call(Transaction $transaction, BlockNumber $blockNumber): string
diff --git a/src/Methods/PersonalClient.php b/src/Methods/PersonalClient.php
index e449b7b..1ee8ef7 100644
--- a/src/Methods/PersonalClient.php
+++ b/src/Methods/PersonalClient.php
@@ -28,13 +28,13 @@ public function listAccounts(): array
         return $addresses;
     }
 
-    public function newAccount(string $password): Address
+    public function newAccount(string $password): ?Address
     {
         $response = $this->client->send(
             $this->client->request(67, 'personal_newAccount', [$password])
         );
 
-        return new Address($response->getRpcResult());
+        return ($response->getRpcResult()) ? new Address($response->getRpcResult()) : null;
     }
 
     public function unlockAccount(Address $address, string $password, int $duration): bool
@@ -46,12 +46,12 @@ public function unlockAccount(Address $address, string $password, int $duration)
         return empty($result) ? false : true;
     }
 
-    public function sendTransaction(Transaction $transaction, string $password): TransactionHash
+    public function sendTransaction(Transaction $transaction, string $password): ?TransactionHash
     {
         $response = $this->client->send(
             $this->client->request(1, 'personal_sendTransaction', [$transaction->toArray(), $password])
         );
-        return new TransactionHash($response->getRpcResult());
+        return ($response->getRpcResult()) ? new TransactionHash($response->getRpcResult()) : null;
     }
 
     public function sign(string $message, Address $address, string $password): string
@@ -62,11 +62,11 @@ public function sign(string $message, Address $address, string $password): strin
         return $response->getRpcResult();
     }
 
-    public function ecRecover(string $message, string $signature): TransactionHash
+    public function ecRecover(string $message, string $signature): ?TransactionHash
     {
         $response = $this->client->send(
             $this->client->request(1, 'personal_ecRecover', [$message, $signature])
         );
-        return new Address($response->getRpcResult());
+        return ($response->getRpcResult()) ? new Address($response->getRpcResult()) : null;
     }
 }